A- (3) prefix meaning "not," from Gk a-, an- "not," from pie base *ne "not" (see un-)

illicit --- 1611 (implied in illicitous), from Fr. illicite (14c.), from L. illicitus "not allowed, unlawful, illegal," from in- "not" + licitus "lawful," pp. of licere "to be allowed."

Illinois --- territory created 1809; name is from a native Algonquian people who called themselves Inoca (1725), also written Ilinouek, Old Ottawa for "ordinary speaker." The modern form represents a 17c. Fr. spelling, pronounced "ilinwe" at that time.

illiterate --- 1556, from L. illiteratus "unlearned, ignorant," from in- "not" + literatus, lit. "furnished with letters."

illuminati --- 1599, pl. of L. illuminatus "enlightened" (in figurative sense), pp. of illuminare (see illumination). Originally applied to a 16c. Spanish sect (the Alumbrados), then to other sects; since 1797 used as a translation of Ger. Illuminaten, name of a secret society founded 1776 in Ingolstadt, Bavaria, and holding deistic and republican principles; hence used generally of free-thinkers and sarcastically of those professing intellectual enlightenment (1816).

illumination --- 1340, "spiritual enlightenment," from O.Fr. illumination, from L. illuminationem (nom. illuminatio), from illuminare "to throw into light," from in- "in" (with assimilation of -n- to the following consonant) + lumen (gen. luminis) "light." Meaning "the action of lighting" is from 1563. Illuminate (M.E. enlumyen) originally meant "decorate written material with gold, silver, bright colors;" sense of "shining light on" first recorded 1563. (Illumine in this sense is from 1375.)

illusion --- c.1340, "act of deception," from O.Fr. illusion "a mocking," from L. illusionem (nom. illusio) "a mocking, jesting, irony," from illudere "mock at," lit. "to play with," from in- "at" + ludere "to play" (see ludicrous). Sense of "deceptive appearance" developed in Eng. c.1374. Illusionist "conjurer, magic act performer" is from 1850. Illusive formed in Eng. 1679; the other adj. form, illusory (1599) is from Fr. illusorie, from L.L. illusorius "of a mocking character," from L. illudere.

illustration --- c.1375, "a spiritual illumination," from O.Fr. illustration, from L. illustrationem (nom. illustratio) "vivid representation" (in writing), lit. "an enlightening," from illustrare "light up, embellish, distinguish," from in- "in" + lustrare "make bright, illuminate." Mental sense of "act of making clear in the mind" is from 1581. Meaning "an illustrative picture" is from 1816. Illustrate "educate by means of examples," first recorded 1612. Sense of "provide pictures to explain or decorate" is 1638.

illustrious --- c.1566, from L. illustris "bright, distinguished, famous," back-formation from illustrare "embellish, distinguish, make famous" (see illustration).

im- --- variant of in- before -b-, -m-, -p-, in the sense of "not" (immobile, impersonal) as well as "in" (implant, impoverish). Many words beginning with im- in Mod.Eng. are transparent (impossible, etc.) and etymologies can be found in listings for their stems. Words listed here are those whose unprefixed form is not an obvious word in Eng. or whose meaning has drifted significantly.

image --- c.1225, "artificial representation that looks like a person or thing," from O.Fr. image, earlier imagene (11c.), from L. imaginem (nom. imago) "copy, statue, picture, idea, appearance," from stem of imitari "to copy, imitate" (see imitate). Meaning "reflection in a mirror" is c.1315. The mental sense was in L., and appears in Eng. c.1374. Sense of "public impression" is attested in isolated cases from 1908 but not in common use until its rise in the jargon of advertising and public relations, c.1958. Imagism as the name of a movement in poetry that sought clarity of expression through use of precise visual images, "hard light, clear edges," was coined 1912 by Ezra Pound.

imagine --- 1340, "to form a mental image of," from O.Fr. imaginer, from L. imaginari "to form a mental picture to oneself, imagine" (also, in L.L. imaginare "to form an image of, represent"), from imago (see image). Sense of "suppose" is first recorded c.1380. Imaginary "not real" is from 1382 (ymaginaire). First record of imagination "faculty of the mind which forms and manipulates images" is from c.1340 (ymaginacion). Imaginative first attested c.1386 (ymaginatyf).

imam --- 1613, from Ar., lit. "leader," lit. "one who precedes," from amma "to go before, precede."

imbecility --- 1533, "weakness, feebleness, impotence," from L. imbecillitatem (nom. imbecillitas) "weakness, feebleness," from imbecillus "weak, feeble," traditionally said to mean "unsupported" (quasi sine baculo), from in- "not" + baculum "a stick." "Weakness in mind" (as opposed to body) was a secondary sense in L. but was not attested in Eng. until 1624. Imbecile is first recorded 1549 as imbecille (adj.) "weak, feeble" (especially in reference to body), from M.Fr. imbecile, from L. imbecillus. As a noun, it is attested from 1802. Traditionally one with a mental age of roughly 6 to 9 (ahead of an idiot but beneath a moron).

imbibe --- c.1386, from O.Fr. embiber "to soak into," from L. imbibere "absorb, drink in, inhale," from in- "in" + bibere "to drink," related to potare "to drink," from PIE *pi-/*po(i)- "to drink (cf. Skt. pati "drinks," panam "beverage;" Gk. pinein "to drink," potos "a drinking;" O.C.S. piti "to drink"). Figurative sense of "mentally drink in" (knowledge, ideas, etc.) was the main one in classical L., first attested in Eng. 1555.

imbrication --- 1650, from Fr. imbrication, from L. imbricare "to cover with tiles," from imbricem (nom. imbrex) "curved roof tile used to draw off rain," from imber (gen. imbris) "rain," from PIE *mbh- (cf. Skt. abhra "cloud, thunder-cloud, rainy weather," Gk. ombros "rain"), from base *nebh- "moist, water" (see nebula).

imbroglio --- 1750, from It. imbroglio, from imbrogliare "confuse, tangle," from in- "in" + brogliare "embroil," probably from M.Fr. brouiller "confuse" (see broil (2)).

imbue --- c.1550, "to cause to absorb" (feelings, opinions, etc.), from M.Fr. imbu (infl. by L. imbutus, pp. of imbuere "moisten, stain"), earlier embu, pp. of emboire, from L. imbibere "drink in, soak in."

imitation --- 1502, from O.Fr. imitacion, from L. imitationem (nom. imitatio) "imitation," from imitari "to copy, portray, imitate," from PIE *im-eto-, from base *aim- "copy." (Related to L. imago, see image). The verb imitate is first recorded 1534.

immaculate --- c.1430, "free from mental or moral pollution, pure," from a fig. use of L. immaculatus "unstained," from in- "not" + maculatus "spotted, defiled," pp. of maculare "to spot," from macula "spot, blemish." The literal sense of "spotlessly clean or neat" is first attested 1735. Immaculate Conception is 1497, from M.Fr. conception immaculée; declared to be an article of faith in 1854.

immanent --- indwelling, inherent, 1535, via Fr., from L.L. immanens, prp. of L. immanere, from in- "in" + manere "to dwell" (see manor). Contrasted with transcendent.

immaterial --- 1398, from M.L. immaterialis "not consisting of matter, spiritual," from L.L. immaterialis, from in- "not" + L.L. materialis (see material). Sense of "unimportant" is first recorded 1698 from material in its 16c. sense of "important."

immature --- 1548, "untimely, premature," from L. immaturus "untimely, unripe," from in- "not" + maturus (see mature). In 16c., usually in ref. to death; modern sense of "not fully developed" first recorded 1641.

immediate --- 1412 (implied in immediately), from O.Fr. immediat, from L.L. immediatus "without anything between," from in- "not" + mediatus, pp. of mediare "to halve," later, "be in the middle," from L. medius "middle" (see medial).

immemorial --- 1602, from Fr. immémorial (16c.) "old beyond memory," from M.L. immemorialis, from in- "not" + memorialis (see memorial). Something immemorial is ancient beyond memory; something immemorable (1552) is not memorable.

immense --- 1490, from M.Fr. immense (1360), from L. immensus "immeasurable, boundless," from in- "not" + mensus "measured," pp. of metiri (see measure).

immersion --- c.1450, from L.L. immersionem (nom. immersio), noun of action from immergere, from L. in- "into" + mergere "plunge, dip" (see merge). Meaning "absorption in some interest or situation" is from 1647. As a method of teaching a foreign language, it is from 1965, trademarked by the Berlitz company.

immigrate --- 1623, from L. immigratum, pp. of imigrare "to remove, go into, move in," from in- "in" + migrare "to move" (see migration). Immigrant "one who immigrates" is first attested 1792 in an Amer.Eng. context.

imminent --- 1528, from L. imminentem (nom. imminens), prp. of imminere "to overhang, impend, be near," from in- "into" + minere "jut out," related to mons "hill" (see mount).

immolate --- 1548, "to sacrifice, kill as a victim," originally an adj. (1534), from L. immolatus, pp. of immolare "to sacrifice," originally "to sprinkle with sacrificial meal," from in- "upon" + mola (salsa) "(sacrificial) meal," related to molere "to grind."

immortal --- deathless, c.1374, from L. immortalis, from in- "not" + mortalis "mortal" (see mortal (adj.)). In ref. to fame, literature, etc., attested from 1514.

immunity --- 1382, "exempt from service or obligation," from L. immunitatem (nom. immunitas) "exemption from performing public service or charge," from immunis "exempt, free," from in- "not" + munis "performing services" (cf. municipal), from PIE *moi-n-es-, suffixed form of base *mei- "to change" (see mutable). Medical sense "protection from disease" is 1879 from Fr. or Ger.

immure --- 1583, from M.L. immurare, lit. "to shut up within walls," from L. in- "in" + murus "wall" (see mural)

immutable --- 1412, from O.Fr. immutable, from L. immutabilis "unchangeable," from in- "not" + mutabilis "changeable," from mutare "to change" (see mutable).

imp --- O.E. impe, impa "young shoot, graft," from impian "to graft," probably an early W.Gmc. borrowing from V.L. *imptus, from L.L. impotus "implanted," from Gk. emphytos, verbal adj. formed from emphyein "implant," from em- "in" + phyein "to plant." Sense of "child, offspring" (1377) came from transfer of word from plants to people, with notion of "newness" preserved. Modern meaning "little devil" (1584) is from common use in pejorative phrases like imp of Satan.

impact (v.) --- 1601, "press closely into something," from L. impactus, pp. of impingere "to push into, dash against" (see impinge). Originally sense preserved in impacted teeth (1876). Sense of "strike forcefully against something" first recorded 1916. Figurative sense began with use as a noun (1817, first in Coleridge) meaning "effect of coming into contact with a thing or person."

impair --- c.1374, earlier ampayre, apeyre (1297), from O.Fr. empeirier, from V.L. *impejorare "make worse," from L. in- "into" + L.L. pejorare "make worse," from pejor "worse." In ref. to driving under the influence of alcohol, first recorded 1951 in Canadian Eng.

impala --- 1875, from Zulu im-pala "gazelle."

impale --- 1530, "to enclose with stakes, fence in," from M.L. impalare "to push onto a stake," from L. in- "in" + pallus "pole." Sense of "pierce with a pointed stake" as torture or punishment first recorded 1613.

impart --- 1477, from M.Fr. impartir, from L. impartire (also impertire) "to share in, divide with another, communicate," from in- "in" + partire "to divide, part."

impartial --- formed in Eng. 1593 from in- "not" + partial (q.v.). First recorded in "Richard II."

impasse --- 1851, from Fr. impasse "impassable road, blind alley, impasse," from in- "not" + M.Fr. passe "a passing," from passer "to pass." Supposedly coined by Voltaire as a euphemism for cul de sac.

impeach --- c.1380, "to impede, hinder, prevent," from Anglo-Fr. empecher, from O.Fr. empeechier "hinder" (12c.), from L.L. impedicare "to fetter, catch, entangle," from L. in- "in" + pedica "shackle," from pes (gen. pedis) "foot." Sense of "accuse a public officer of misconduct" first recorded 1568, via confusion with L. impetere "attack, accuse."

impeccable --- 1531, "not capable of sin," from M.Fr. impeccable (15c.), from L. impeccabilis "not liable to sin," from in- "not" + pecare "to sin," of unknown origin.

impecunious --- lacking in money, 1596, from in- "not" + L. pecuniosus "rich," from pecunia "money, property."

impediment --- 1398, from L. impedimentem "hindrance," from impedire "impede," lit. "to shackle the feet," from in- "in" + pes (gen. pedis) "foot." Impede (1605) is first attested in Shakespeare.

impel --- 1490, from L. impellere "to push, strike against, drive forward, urge on," from in- "into" + pellere "to push, drive."

impend --- 1599, from fig. use of L. impendere "to hang over, to be imminent," from in- "in" + pendere "hang" (see pendant).

imperative --- 1530, from L.L. imperativus "pertaining to a command," from imperatus "commanded," pp. of imperare "to command, to requisition," from in- "in" + parare "beget, bear" (see pare).

imperfect --- c.1340, imperfite, from O.Fr. imparfait, from L. imperfectus "unfinished, incomplete." Replaced mid-1500s by L. form.

imperial --- c.1374, "having a commanding quality," from O.Fr. imperial (12c.), from L. imperialis "of the empire or emperor," from imperium (see empire). Meaning "of or pertaining to an empire" (especially the Roman) is from 1390. An imperialist originally was "an adherent of an emperor," such as the emperor of Germany, France, China, etc. The shift in meaning came via the British Empire, which involved a worldwide colonial system. Imperialism, in the sense of "one country's rule over another," first recorded 1878. Picked up disparagingly in Communist jargon 1918; imperialist (n.) in this sense first recorded 1963.

imperious --- 1541, from L. imperiosus "commanding, mighty, powerful," from imperium "empire, command" (see empire).

impermeable --- 1697, from Fr. imperméable, from L.L. impermeabilis, from in- "not" + permeabilis (see permeable).

imperscriptable --- unrecorded, without written authority, 1832, used only with right. From L. in- "not" + perscribere "to write down."

impersonal --- 1520, a grammatical term, from L.L. impersonalis, from in- "not" + personalis "personal." Sense of "not connected with any person" is from 1630; that of "not endowed with personality" is from 1842.

impersonate --- 1624, "to invest with a personality," from L. in- "in" + persona "person." Sense of "to assume the person or character of" is first recorded 1715. Impersonator in this sense is from 1853.

impertinent --- c.1380, "unconnected, unrelated," from L.L. impertinentem (nom. impertinens) "not belonging," lit. "not to the point," from L. in- "not" + pertinens (see pertinent). Sense of "rudely bold" is 1681, probably modeled on similar use in Fr., esp. by Molière, from notion of meddling with what is beyond one's proper sphere.

imperturbable --- c.1450, from L.L. imperturbabilis "that cannot be disturbed" (Augustine), from in- "not" + *perturbabilis, from L. perturbare "to confuse, disturb" (see perturb).

impervious --- 1650, from L. impervius "that cannot be passed through," from in- "not" + pervius "letting things through," from per "through" + via "road."

impetuous --- c.1489, from M.Fr. impétueux (13c.), from L.L. impetuosus "impetuous, violent," from L. impetus "attack" (see impetus).

impetus --- 1641, from L. impetus "attack, assault, onset, impulse, violence, vigor, force, passion," related to impetere "to attack," from in- "into" + petere "aim for, rush at" (see petition).

impinge --- 1535, from L. impingere "drive into, strike against," from in- "in" + pangere "to fix, fasten." Sense of "encroach, infringe" first recorded 1758.

implacable --- 1522, from O.Fr. implacable, from L. implacabilis "unappeasable," from in- "not" + placabilis "easily appeased" (see placate).

implant (v.) --- 1545, from Fr. implanter "to insert, engraft," from in- "in" + planter "to plant" (see plant (n.)). The noun meaning "anything implanted within the body" is from 1890.

implement (n.) --- 1454, from L.L. implementem "a filling up" (as with provisions), from L. implere "to fill," from in- "in" + plere "to fill" (see plenary). Sense of "tool" is 1538, from notion of things provided to do work, that which "fills up" a house, etc. The verb is 1806, originally chiefly in Scot., where it was a legal term meaning "fulfillment." It led to the wretched formation implementation, first recorded 1926.

implication --- involvement, interweaving, c.1430, from L. implicationem (nom. implicatio) "interweaving, entanglement," from implicatus, pp. of implicare "involve, entangle, connect closely," from in- "in" + plicare "to fold" (see ply). Implicate in the sense of "involve a person in a crime, charge, etc." is from 1797.

implicit --- 1599, from L. implicitus, later variant of implicatus, pp. of implicare (see implicate).

implore --- 1500, from L. implorare "call for help, beseech," originally "invoke with weeping," from in- "upon" + plorare "to weep, cry out."

implosion --- a bursting inward, 1877, modeled on explosion (q.v.). Originally in ref. to effect of deep sea pressures. Fig. sense is from 1960. Verb implode is from 1881.

imply --- c.1374, "to enfold, enwrap, entangle" (the classical L. sense), from O.Fr. emplier, from L. implicare "involve" (see implicate). Meaning "to involve something unstated as a logical consequence" first recorded 1529. The distinction between imply and infer is in "What do you imply by that remark?" But, "What am I to infer from that remark?"

impolite --- 1612, "unrefined, rough," from L. impolitus, from in- "not" + politus "polished" (see polite). Sense of "discourteous, ill-mannered" is from 1739.

import (v.) --- c.1430, "convey information, express, make known," from L. importare "bring in, convey," from in- "into" + portare "to carry" (see port (1)). Sense of "bring in goods from abroad" first recorded 1508. The noun meaning "consequence, importance" is from 1588; sense of "that which is imported" is from 1690.

important --- 1444, from M.Fr. important, from M.L. importantem (nom. importans), prp. of importare "be significant in," from L. importare "bring in" (see import).

importune --- c.1425 (implied in importunely), from M.Fr. importuner, from M.L. importunari "to make oneself troublesome," from L. importunus "unfit, troublesome," originally "having no harbor" (i.e. "difficult to access"), from in- "not" + portus "harbor" (see port). Importunate is 1529, from L. importunus.

impose --- 1484, "to lay (a crime, etc.) to the account of," from M.Fr. imposer, from in- "into" + poser "put, place" (see pose). Sense of "to lay on as a burden" first recorded 1581.

imposition --- c.1374, "the levying of taxes, a tax, duty," from O.Fr. imposition (1317), from L. impositionem (nom. impositio) "a laying on," from imponere "to place upon," from in- "into" + ponere "to put, place" (see position). Sense of "the act of putting (something) on (something else)" is from 1597. Meaning "an act of imposing" (on someone) first recorded 1632 (see impose).

impostor --- 1586, from M.Fr. imposteur, from L.L. impostorem (nom. impostor), agent noun from impostus, collateral form of impositus, pp. of imponere "place upon, impose upon, deceive," from in- "in" + ponere "to put place" (see position). Imposture "act of willfully deceiving others" first recorded 1537.

impotent --- 1390, "physically weak," from O.Fr. impotent "powerless," from L. imponentem (nom. impotens) "lacking control, powerless," from in- "not" + ponentem (nom. potens) "potent." Meaning "having no power to accomplish anything" is from 1444; that of "completely lacking in sexual power" is from 1594 (implied in impotency).

impound --- 1554, "to shut up in a pen or pound," from in- "in" + pound (n.). Originally of cattle seized by law.

impracticable --- 1677, from in- "not" + practicable. "Incapable of being done." Impractical, in the same sense, dates from 1865.

imprecation --- 1448, from L. imprecationem (nom. imprecatio), from imprecatus, pp. of imprecari "invoke, pray," from in- "within" + precari "to pray, ask beg, request." "Current limited sense is characteristic of human nature." [Weekley]

impregnable --- 1430, imprenable, from M.Fr. imprenable, from O.Fr. in- "not" + prenable "assailable, vulnerable," from stem of prendre "to take, grasp," from L. prehendere (see prehensile). With intrusive -g- 16c., on model of deign, reign, etc.

impregnate (v.) --- 1605, from L.L. imprægnatus "pregnant," pp. of imprægnare "to render pregnant," from in- "in" + prægnare "make pregnant" (see pregnant).

impresario --- 1746, from It. impresario "operatic manager," lit. "undertaker (of a business)," from impresa "undertaking," fem. of impreso, pp. of imprendere "undertake," from V.L. imprendere, from L. in- "onto" + prehendere "to grasp" (see prehensile).

imprescriptible --- inalienable, not subject to prescription, 1563, from in- "not" + L. praescriptus, pp. of praescribere "to write beforehand" (see prescribe). Usually with right.

impress (v.) --- c.1374, "to apply with pressure, make a permanent image in," from L. impressus, pp. of imprimere "press into or upon, stamp," from in- "into" + premere "to press" (see press (v.1)). Fig. sense of "have a strong effect on the mind or heart" is from 1413. Sense of "to levy for military service" is from 1596, a meaning more from press (v.2). Impressionable formed 1836 on Fr. model, Impressive was originally (1593) "capable of being easily impressed;" sense of "making an impression on the mind or senses" is from 1775.

impressionist --- as a style of painting aiming to represent overall impressions rather than exact details, first attested in Eng. 1876, coined in Fr. 1874 by Fr. critic Louis Leroy ("école impressionniste") in a disparaging ref. to Monet's sunset painting "Impression, Soleil Levant." Later extended to other arts.

imprimatur --- 1640, from Mod.L. "let it be printed," the formula of a book licenser, third person singular present subjunctive passive of L. imprimere "to print" (see impress). Originally of state license to print books, later only of Roman Catholic Church.

imprint --- c.1374, from O.Fr. empreinter, from empreinte, noun use of fem. pp. of eimpreindre "to impress, imprint," from V.L. *impremere, from L. imprimere "to impress, imprint" (see impress).

impromptu --- 1669 (adv.), 1764 (adj.), from Fr. impromptu (1659), from L. in promptu "in readiness," from in "in" + promptu, abl. of promptus "readiness," from pp. of promere "to bring out," from pro- "before, forward, for" + emere "to obtain" (see exempt).

improper --- 1531 (implied in improperly) "not true," from Fr. impropre (14c.), from L. improprius, from in "not" + proprius (see proper). Meaning "not suited, unfit" is from 1570; that of "not in accordance with good manners, modesty, decency" is from 1739.

improve --- 1473, "to use to one's profit," from Anglo-Fr. emprouwer "to turn to profit" (1292), from O.Fr. en-, causative prefix, + prou "profit," from L. prode "advantageous" (see proud). Meaning "to raise to a better quality or condition" first recorded 1617. Phrase improve the occasion retains the etymological sense. Meaning "to turn land to profit" (by clearing it, erecting buildings, etc.) was in Anglo-Fr. (13c.) and was retained in the American colonies.

improvident --- 1514, from L. improvidus "not foreseeing" (see improvise). It retains a stronger connection with the "provide" aspect of L. providere.

improvisation --- 1786, "act of improvising musically," from Fr. improvisation, from improviser "compose or say extemporaneously," from It. improvvisare, from improvviso "unforeseen, unprepared," from L. improvisus, from in- "not" + provisus "foreseen," also "provided," pp. of providere "foresee, provide." Improvise first recorded 1826.