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

undercover --- 1854, sheltered," from under + cover. Sense of "operating secretly" attested from 1920.

undercurrent --- 1663, "stream of water or air flowing beneath the surface or beneath another current," a hybrid formed from under + current. The fig. sense of "suppressed or underlying character" is attested from 1817.

undercut (v.) --- 1382, "to cut down or off," from under + cut (v.). In the commercial sense of "to sell at lower prices" (or work at lower wages) it is first attested 1884. Fig. sense of "render unstable, undermine" is recorded from 1955, from earlier lit. meaning "cut so as to leave the upper portion larger than the lower" (1874).

underdeveloped --- 1892, in the photography sense, under + pp. of develop. In ref. to countries or regions, recorded from 1949.

underdog --- the beaten dog in a fight, 1887, from under + dog. Cf. top dog "dominant person in a situation or hierarchy."

underdone --- 1683, in ref. to cooked meat, from under + pp. of do.

underdressed --- too plainly dressed, 1784, from under + pp. of dress (v.).

under-employed --- 1908, "not used to optimum capacity," originally in ref. to working persons, from under + pp. of employ.

underestimate (v.) --- 1812, "to estimate at too low an amount," from under + estimate (v.). Meaning "to rank too low, undervalue" is recorded from 1850.

underfoot (adv.) --- c.1200, underfot "under the feet," from under + foot. Cf. M.Du. ondervoete. As an adj., attested from 1596; in ref. to persons, "continually in the way," it is recorded from 1891.

undergo --- O.E. undergan "undermine," from under + gan (see go). Cf. M.Du. ondergaen, O.H.G. untarkun, Ger. untergehen, Dan. undergaa. Sense of "submit to, endure" is attested from c.1300. Meaning "to pass through" (an alteration, etc.) is attested from 1634.

undergraduate --- 1630, a hybrid formed from under + graduate (n.). British used fem. form undergraduette in 1920s-30s.

underground (adv.) --- 1571, "below the surface," from under + ground (n.). Adj. is attested from 1610; fig. sense of "hidden, secret" is attested from 1632; adj. meaning "subculture" is from 1953, from World War II application to resistance movements against German occupation, on analogy of the dominant culture and Nazis. Noun sense of "underground railway" is from 1887 (phrase underground railway itself is attested from 1834).

Underground Railroad --- network of U.S. anti-slavery activists helping runaways elude capture, attested from 1852 but said to date from 1831, coined in jest by bewildered trackers after their slaves vanished without a trace.

undergrowth --- 1600, from under + growth (see grow).

underhand (adv.) --- O.E. under hand "in subjection," from under + hand. Sense of "secret, stealthy, surreptitious" first recorded 1538. For sense development, cf. M.Du. onderhanden "by degrees, slowly," Du. onderhandsch "secret, private." The adj. is attested from 1545.

underlay --- O.E. under lecgan "to support by placing something beneath;" see under + lay (v.).

underlie --- O.E. under licgan "to be subordinate to, to submit to;" see under + lie (v.2). Meaning "to lie under or beneath" is attested from 1600; fig. sense of "to be the basis of" is attested from 1852 (implied in underlying).

underline (v.) --- 1721, from under + line (v.). Cf. Du. onderlijnen. The noun is attested from 1888.

underling --- c.1175, from under + dim. suffix -ling.

undermine --- c.1300, undermyne, from under + mine (v.). The fig. sense is attested from c.1430. Cf. Du. ondermijnen, Dan. underminere, Ger. unterminiren.

underneath --- O.E. underneoðan, from under + neoðan "below" (see beneath).

under-nourished --- 1910, from under + pp. of nourish.

underpants --- 1931, from under + pants. Drove out drawers, knickers in this sense.

underpass --- 1904, Amer.Eng., from under + pass.

underpinning --- 1489, "action of supporting or strengthening from beneath," from under + pp. of pin (v.). Fig. sense of "prop, support" is recorded from 1589.

underprivileged (adj.) --- 1896, from under + pp. of privilege (v.). Noun use is attested from 1935.

under-rate --- 1650, "to esteem at too little worth," from under + rate (v.).

underscore (v.) --- 1771, "to draw a line under," from under + score (v.). The fig. sense of "to emphasize" is attested from 1891. Noun meaning "a line drawn below (something)" is recorded from 1901.

under-sea --- 1613, from under + sea.

undershirt --- 1648, from under + shirt. Cf. N.Fris. onnersjürt, Dan. underskjorte.

undershoot --- 1661, "to shoot too low," from under + shoot (v.). In ref. to aircraft or pilots, recorded from 1918. Undershot as a type of water wheel is recorded from 1610.

underside --- c.1680, from under + side (n.). Cf. Du. onderzijde, Dan. underside, Ger. unterseite.

undersign (v.) --- 1580, from under + sign (v.).

understand --- O.E. understandan "comprehend, grasp the idea of," probably lit. "stand in the midst of," from under + standan "to stand" (see stand). If this is the meaning, the under is not the usual word meaning "beneath," but from O.E. under, from PIE *nter- "between, among" (cf. Skt. antar "among, between," L. inter "between, among," Gk. entera "intestines;" see inter-). But the exact notion is unclear. Perhaps the ult. sense is "be close to," cf. Gk. epistamai "I know how, I know," lit. "I stand upon." Similar formations are found in O.Fris. (understonda), M.Dan. (understande), while other Gmc. languages use compounds meaning "stand before" (cf. Ger. verstehen, represented in O.E. by forstanden ). For this concept, most I.E. languages use fig. extensions of compounds that lit. mean "put together," or "separate," or "take, grasp."

understanding --- O.E. understandincge "comprehension," from understand (q.v.). Meaning "mutual agreement" is attested from 1803.

understatement --- 1799, from under + statement. Understated, with ref. to clothing, is recorded from 1957.

understorey --- 1945, in ref. to forest vegetation, from under + storey.

understudy (v.) --- 1874, in the theatrical sense, from under + study (v.). The noun is attested from 1882.

undertake --- c.1200, "to entrap," in the same sense as O.E. underniman (cf. Du. ondernemen, Ger. unternehmen), of which it is a partial loan-translation, from under + take. Cf. also Fr. entreprendre "to undertake," from entre "between, among" + prendre "to take." The under in this word may be the same one that also may form the first element of understand. Meaning "to accept" is attested from c.1250; that of "to take upon oneself, to accept the duty of" is from c.1300. Undertaking "enterprise" is recorded from c.1425.

undertaker --- c.1400, "a contractor or projector of any sort," agent noun from undertake (q.v.). The specialized sense (1698) emerged from funeral-undertaker.

undertone --- 1762, "low or subdued tone," from under + tone. Fig. sense of "undercurrent of feelings, etc.," is attested from 1861.

undertow --- 1817, from under + tow.

under-utilize --- 1954, from un- (1) "not" + pp. of utilize.

undervalue --- 1596, "to rate as inferior in value" (to), from under + value (v.). Sense of "to estimate or esteem too low" is recorded from 1611. Meaning "to rate at too low a monetary value" is attested from 1622.

underwater (adj.) --- 1627, from under + water.

underway (adv.) --- 1934, of ships, "having begun to move," from under + way. In ref. to projects, activities, etc., it is attested from 1935.

underwear --- 1872, from under + wear (n.). So called because it is worn under one's clothing.

underweight --- 1899, from under- + weight.

underwhelm --- 1956, a facetious play on overwhelm.

underworld --- 1608, "the lower world, Hades," also "the earth," as distinguished from heaven (1609). Cf. Ger. unterwelt, Du. onderwereld, Dan. underverden. Meaning "lower level of society" is first recorded 1890; "criminals and organized crime collectively" is attested from 1900.

underwrite --- c.1430, loan-translation of L. subscribere (see subscribe). Used literally at first; modern sense of "to accept the risk of insurance" (1622) is from notion of signing a marine insurance policy. Meaning "to support by a guarantee of money" is recorded from 1890.

undeserved --- c.1374, from un- (1) "not" + pp. of deserve.

undesirable (adj.) --- 1667, "not to be desired, objectionable," from un- (1) "not" + desire + -able. The noun meaning "undesirable person or thing" is first attested 1883. Undesired "not asked or invited" is recorded from 1470.

undetected --- c.1593, from un- (1) "not" + pp. of detect. Undetectable is recorded from 1863.

undetermined --- 1442, from un- (1) "not" + pp. of determine.

undeveloped --- 1736, from un- (1) "not" + pp. of develop. In ref. to film, it is attested from 1939.

undies --- 1906, diminutive euphemistic abbreviation for women's underwear (or undergarments).

undifferentiated --- 1862, from un- (1) "not" + pp. of differentiate (see difference).

undigested --- 1528, from un- (1) "not" + pp. of digest (v.). Fig. sense is recorded from c.1610.

undignified --- 1689, of clergy, "not holding a position of dignity," from un- (1) "not" + pp. of dignify (see dignity). Meaning "lacking in dignity of manner" is attested from 1782.

undine --- 1821, from Mod.L. Undina (1657), coined by Paracelsus ("De Nymphis") for a water spirit in his alchemical system, from L. unda "a wave" (see water). Popularized by Ger. romance "Undine, eine Erzählung" (1811) by Baron F.H.C. La Motte Fouqué. Undinism (1928) was coined by sex researcher Havelock Ellis to describe the fetish for urine (which Ellis had); nowadays it would be called urophilia.

undisciplined --- 1382, "untrained," from un- (1) "not" + pp. of discipline (v.). Cf. Ger. undisciplinirt, Swed. odisciplinerad. Specific meaning "not subject to military discipline" is attested from 1718.

undisclosed --- 1570, from un- (1) "not" + pp. of disclose.

undiscovered --- 1542, from un- (1) "not" + pp. of discover.

undisguised --- c.1500, in ref. to things, from un- (1) "not" + pp. of disguise. Of persons, attested from 1671.

undismayed --- 1615, from un- (1) "not" + pp. of dismay.

undisputed --- 1570, "not argued with," from un- (1) "not" + pp. of dispute. Meaning "not called into question" is attested from 1625.

undistinguished --- 1598, "not kept distinct," from un- (1) "not" + pp. of distinguish. Meaning "not elevated above others" is attested from 1600.

undisturbed --- 1610, from un- (1) "not" + pp. of disturb.

undivided --- c.1412, from un- (1) "not" + pp. of divide.

undo --- O.E. undon "to unfasten and open" (a window or door), "to unfasten by releasing from a fixed position," from un- (2) + do. Undone "not accomplished" is recorded from c.1300; sense of "destroyed" is recorded from 1340; the notion is of "to annul something that was done." Undoing "action of bringing to ruin" is recorded from 1398.

undocumented --- 1883, from un- (1) "not" + pp. of document (v.).

undomesticated --- 1834, from un- (1) "not" + pp. of domesticate (see domestic). Undomestic "not caring for home life" is recorded from 1754.

undoubted --- c.1460, from un- (1) "not" + pp. of doubt (v.).

undress (v.) --- 1596, "to shed one's clothing," from un- (2) + dress (v.). Trans. sense of "to strip off (someone's) clothing" is recorded from 1615. The noun meaning "state of partial or incomplete dress" is attested from 1685. Undressed "naked (or nearly so)" is recorded from 1613.

undue --- 1387, "not owing or payable," from un- (1) "not" + pp. of due. Formed on model of O.Fr. indeu, L. indebitus. Meaning "not appropriate, unseasonable" is recorded from 1398. Sense of "unjustifiable" is attested from 1399 (implied in unduly). Meaning "excessive" is first recorded 1684.

undulation --- 1646, from M.L. *undulatio, from L.L. undulatus "wavy, undulated," from undula "wavelet," dim. of L. unda "wave" (see water). The verb undulate is attested from 1664.

undying --- c.1300, "immortal," from un- (1) "not" + pp. of die (v.). Fig. sense, of feelings, etc., is recorded from c.1765.

unearned --- c.1200, from un- (1) "not" + pp. of earn. Unearned income is recorded from 1889.

unearth --- to dig up, c.1450, from un- (2) + earth (v.) "to bury in the ground" (see earth).

unearthly --- 1611, "heavenly, sublime," from un- (1) "not" + earthly (see earth). Sense of "ghostly, weird" first recorded 1802.

uneasy --- c.1290, "not comforting," from un- (1) "not" + easy. Meaning "disturbed in mind" is attested from 1680.

uneducated --- 1588, from un- (1) "not" + pp. of educate.

unemotional --- 1876, from un- (1) "not" + emotional (see emotion).

unemployed --- 1600, "at leisure, not occupied," from un- (1) "not" + pp. of employ. Meaning "temporarily out of work" is from 1667. The noun meaning "unemployed persons collectively" is from 1782; unemployment first recorded 1888.

unencumbered --- 1722, from un- (1) "not" + pp. of encumber.

un-English --- lacking in qualities regarded as typically English, 1633, from un- (1) "not" + English (1).

unenlightened --- 1662, "not lit up," from un- (1) "not" + pp. of enlighten. Meaning "not mentally illuminated" is attested from c.1656.

unequal --- 1535, "unjust, unfair," from un- (1) "not" + equal. Meaning "not the same in amount, size, quality, etc." is recorded from 1565. Sense of "inadequate, insufficient" (to some task) is attested from 1694.

unequivocal --- 1784, from un- (1) "not" + equivocal (see equivocation).

unerring --- 1645 (implied in unerringly), from un- (1) "not" + gerundive of err.

unethical --- 1871, from un- (1) "not" + ethical (see ethics).

uneven --- O.E. unefen "unequal," from un- (1) "not" + even. Cf. O.Fris. oniovn, M.Du. oneven, O.H.G. uneban, Ger. uneben, O.N. ujafn. Meaning "irregular, broken, rugged" (in ref. to terrain, etc.) is recorded from c.1275.

uneventful --- 1800, from un- (1) "not" + eventful (see event).

unexamined --- 1495, from un- (1) "not" + pp. of examine.

unexceptionable --- 1664, from un- (1) "not" + exception (see except) + -able.

unexpected --- c.1586, from un- (1) "not" + pp. of expect.

unexplained --- 1721, from un- (1) "not" + pp. of explain.

unfailing --- 1382, "never coming to an end, unceasing," from un- (1) "not" + gerundive of fail.

unfair --- O.E. unfægr "unlovely," from un- (1) "not" + fair. Cf. O.N. ufagr, Goth. unfagrs. Meaning "wicked, evil, bad" is recorded from c.1300. Sense of "not equitable, unjust" is first recorded 1713.

unfaithful --- 1340 (implied in unfaithfully) "acting falsely," from un- (1) "not" + faithful (see faith). In M.E. it also had a sense of "infidel, unbelieving, irreligious" (1382). Sense of "not faithful in marriage" is attested from 1828.

unfamiliar --- 1594, from un- (1) "not" + familiar.

unfashionable --- 1563, "incapable of being shaped," from un- (1) "not" + fashionable (see fashion). Meaning "not in accordance with prevailing fashion" is attested from 1648.

unfasten --- c.1225, from un- (2) + fasten.

unfathomable --- 1617, originally in the fig. sense, of feelings, conditions, etc., from un- (1) "not" + fathom (v.) + -able. Lit. sense attested from c.1676.

unfavorable --- 1460 (implied in unfavorably), from un- (1) "not" + favor (v.) + -able.

unfeeling --- late O.E., "having no sensation," from un- (1) "not" + feeling (see feel). Meaning "devoid of kindly or tender feelings" is recorded from 1596.

unfeigned --- c.1374, "sincere, genuine, true, real," from un- (1) "not" + pp. of feign.

unfetter --- 1362, from un- (2) + fetter (v.). The fig. sense is recorded from c.1374.

unfinished --- 1553, from un- (1) "not" + pp. of finish.

unfit (adj.) --- 1545, "not suitable" (in ref. to things), from un- (1) "not" + pp. of fit (see fit (adj.)). In ref. to persons or human qualities, attested from 1551. The verb meaning "to render unfit" is recorded from 1611.

unflappable --- 1958, from un- (1) "not" + flap (v.) + -able. Originally used in ref. to Harold Macmillan, British P.M. 1957-63.

unflattering --- 1581, from un- (1) "not" + gerundive of flatter.

unfledged --- 1602, of persons, "immature, not experienced," from un- (1) "not" + pp. of fledge. Lit. sense of "not yet covered in feathers" is recorded from 1611.

unflinching --- 1728, from un- (1) "not" + gerundive of flinch.

unfold --- O.E. unfealdan, "to open or unwrap the folds of," also fig., "to disclose, reveal," from un- (2) + fold (v.). Cf. M.Du. ontvouden, Ger. entfalten. Refl. sense is attested from c.1374.

unforeseen --- 1651, from un- (1) "not" + pp. of foresee. Cf. M.Du. onvoresien, Du. onvoorzien, M.H.G. unvorsen.

unforgettable --- 1806, from un- (1) "not" + forgetable (see forget).

unforgiven --- 1425, from un- (1) "not" + pp. of forgive. Unforgiving is attested from 1713.

unformed --- 1325, from un- (1) "not" + pp. of form (v.).

unfortunate (adj.) --- 1530, "unlucky," from un- (1) "not" + pp. of fortunate (see fortune). In late 18c.-early 19c., unfortunate woman was a polite way to say "prostitute." The noun meaning "one who is not fortunate" is recorded from 1638. Unfortunately is attested from 1548, originally "not successfully, to a regrettable extent." The proper meaning is now rare; the main modern sense of "sad to say" is first recorded 1706 in parenthetical or detached use.

unfounded --- 1648, "having no foundation or basis," from un- (1) "not" + pp. of found (1).

unfree --- c.1300, from un- (1) "not" + free (adj.). Cf. M.Du. onvri, O.H.G. unfri, Ger. unfrei, M.Da. ufri.

unfrequented --- 1588, from un- (1) "not" + pp. of frequent (v.).

unfriendly --- 1425, "not characteristic of friends," from un- (1) "not" + friendly (see friend). Cf. M.Du. onvriendelijc, M.H.G. unvriuntlich, Ger. unfreundlich. Meaning "hostile, inimical" is recorded from 1483. A noun unfriend "enemy" is recorded from c.1275, chiefly in Scottish, still in use 19c.

unfruitful --- 1388, "barren," from un- (1) "not" + fruitful (see fruit). Originally lit.; fig. sense is attested from c.1400.

unfulfilled --- 1382, from un- (1) "not" + pp. of fulfill.

unfunny --- 1858, from un- (1) "not" + funny.

unfurl --- 1641, from un- (2) + furl (v.).

unfurnished --- 1541, "not equipped, unprepared," from un- (1) "not" + pp. of furnish. In ref. to houses, apartments, etc., "not provided with furniture," it is recorded from 1581.

ungainly --- 1611, originally "unfit, improper," from M.E. ungeinliche, from ungein (c.1400) "inconvenient" (from un- (1) "not" + O.N. gegn "convenient") + -like.

ungird --- O.E. ongyrde, from un- (2) + gird. Cf. M.Du. ontgorden, O.H.G. ingurten, Ger. entgürten.

unglue --- 1548, from un- (2) + glue (v.). Unglued in fig. sense is recorded from 1922.

ungodly --- 1526, "irreligious, not god-fearing, not in accordance with the laws of God," from un- (1) "not" + pp. of godly (adj.). Cf. M.Du. ongodelijc, Ger. ungöttlich, M.Swed. ogudhlik. Colloquial sense of "outrageous, dreadful" is recorded from 1887.

ungrammatical --- 1654, from un- (1) "not" + grammatical (see grammar).

ungrateful --- 1553, from un- (1) "not" + grateful.

ungual --- pertaining to a nail or claw, 1834, from L. unguis "a claw, nail" (cognate with Gk. onyx, O.E. nægel, O.N. nagl "nail;" see nail).

unguarded --- 1593, "not furnished with a guard," from un- (1) "not" + pp. of guard. Sense of "not on one's guard, not taking heed" is attested from 1640.

unguent --- ointment, c.1440, from L. unguentem "ointment," from stem of unguere "to anoint or smear with ointment," from PIE base *ongw- "to salve, anoint" (cf. Skt. anakti "anoints, smears," Armenian aucanem "I anoint," O.Pruss. anctan "butter," O.H.G. ancho, Ger. anke "butter," O.Ir. imb, Welsh ymenyn "butter").

ungulate (adj.) --- hoofed, 1802, from L.L. ungulatus "hoofed," from ungula "hoof, claw, talon," dim. (in form but not sense) of unguis "nail" (see ungual). Ungulata, the order of hoofed mammals, is recorded from 1839.

unhallowed --- O.E. unhalgod, from un- (1) "not" + pp. of hallow.

unhand --- 1602, "to release from one's grasp," from un- (2) + verbal derivative of hand (n.).

unhappy --- c.1300, "causing misfortune or trouble (to oneself or others)," from un- (1) "not" + happy. Meaning "unfortunate, unlucky" is recorded from 1375; sense of "miserable, wretched" is recorded from 1390 (originally via misfortune or mishap). Unhappily is attested from c.1340 (cf. O.N. unheppiliga).

unharmed --- 1340, from un- (1) "not" + pp. of harm.

unharness --- c.1435, "divest of armor," from un- (2) + harness (v.). Cf. Du. ontharnassen "to disarm." Meaning "to free (a horse) from harness" is recorded from 1611.

unhealthy --- 1595, "injurious to health," from un- (1) "not" + healthy. Earlier unhealthsome (1544), unhealthful (1580). Of persons, "sickly," it is attested from 1611.

unheard --- c.1300 "not detected by sense of hearing," from un- (1) "not" + pp. of hear. Meaning "unknown, new" is attested from c.1375 (O.E. had ungehered in this sense). Usually with of since 1592. Cf. O.N. oheyrðr, Dan. uhørt, M.Du. ongehoort, O.H.G. ungehoret.

unhinge --- used earlier in the mental sense of "to disorder" the mind, etc. (1612) than in the literal one of "to take (a door, etc.) off its hinges" (1616); from un- (2) + a verb derivative of hinge.

unhitch --- 1622, from un- (2) + hitch (v.).

unholy --- O.E. unhalig, "impious, profane, wicked," from un- (1) "not" + halig (see holy). Cf. M.Du. onheilich, O.N. uheilagr, Dan. unhellig, Swed. ohelig. In ref. to actions, it is attested from 1382. Colloquial sense of "awful, dreadful" is recorded from 1842.

unhorse --- 1390, "to throw (someone) from his horse," from un- (2) + verbal derivative of hand (n.). Cf. M.Du. ontorsen.

unh-unh --- sound expressing negation or denial, attested from 1951.

uni- --- comb. form meaning "having one only," from L. uni-, comb. form of unus (see one).

Uniate --- pertaining to an Eastern Christian church that acknowledges the supremacy of the Pope, 1833, from Rus. uniyat, from unia "unity, union," from L. unus "one" (see one).

unicameral --- 1853, from uni- "one" + L.L. camera "chamber" (see camera).

unicorn --- c.1225, from O.Fr. unicorne, from L.L. unicornus (Vulgate), from noun use of L. unicornis (adj.) "having one horn," from uni- "one" (see uni-) + cornus "horn" (see horn). The L.L. word translates Gk. monoceros, itself rendering Heb. re'em, which was probably a kind of wild ox. According to Pliny, a creature with a horse's body, deer's head, elephant's feet, lion's tail, and one black horn two cubits long projecting from its forehead. Cf. Ger. Einhorn, Welsh ungorn, Bret. uncorn, O.C.S. ino-rogu.

unicycle --- 1869, Amer.Eng., from L. uni- "one" (see uni-) + -cycle, from bicycle (from Gk. kyklos "circle, wheel").

unidentified --- 1860, from un- (1) "not" + pp. of identify.

uniform (adj.) --- 1540, "of one form," from M.Fr. uniforme (14c.), from L. uniformis "having one form," from uni- "one" (see uni-) + forma "form" (see form). The noun meaning "distinctive clothes worn by one group" is first attested 1748, from Fr. uniforme.

uniformity --- 1432, from O.Fr. uniformite (14c.), from L.L. uniformitatem (nom. uniformitas), from L. uniformis (see uniform).

unify --- 1502, "to make into one," from M.Fr. unifier (14c.), from L.L. unificare "make one," from L. uni- "one" (see uni-) + root of facere "to make" (see factitious). Unification is attested from 1851; the Unification Church was founded 1954 in Korea by Sun Myung Moon. Unified is attested from 1862. Unified (field) theory in physics is recorded from 1935.