- water-ski (n.)
- 1931, from water (n.1) + ski (n.). As a verb from 1953.
- unpalatable (adj.)
- 1680s, from un- (1) "not" + palatable (adj.). Related: Unpalatably.
- unpaved (adj.)
- 1530s, from un- (1) "not" + past participle of pave (v.).
- unperturbed (adj.)
- early 15c., from un- (1) "not" + past participle of perturb (v.).
- unpleasant (adj.)
- 1530s, from un- (1) "not" + pleasant (adj.). Related: Unpleasantly.
- unrestrained (adj.)
- 1580s, from un- (1) "not" + past participle of restrain (v.). Related: Unrestrainedly.
- unrelenting (adj.)
- 1580s, from un- (1) "not" + present participle of relent (v.). Related: Unrelentingly.
- unreformed (adj.)
- 1520s, from un- (1) "not" + past participle of reform (v.).
- unquestionable (adj.)
- c. 1600, from un- (1) "not" + questionable (adj.). Related: Unquestionably.
- unprovoked (adj.)
- 1580s, from un- (1) "not" + past participle of provoke (v.).
- unprofitable (adj.)
- early 14c., from un- (1) "not" + profitable (adj.). Related: Unprofitably.
- unproductive (adj.)
- 1756, from un- (1) "not" + productive (adj.). Related: Unproductively; unproductiveness.
- unpretentious (adj.)
- 1859, from un- (1) "not" + pretentious (adj.). Related: Unpretentiously; unpretentiousness.
- unprepared (adj.)
- 1540s, from un- (1) "not" + past participle of prepare (v.).
- unprejudiced (adj.)
- 1610s, from un- (1) "not" + past participle of prejudice (v.).
- unpredictable (adj.)
- 1840, from un- (1) "not" + predictable (adj.). Related: Unpredictably; unpredictability.
- unprecedented (adj.)
- 1620s, from un- (1) "not" + precedented. In common use from c. 1760.
- unsafe (adj.)
- 1590s, "involving risk or danger," from un- (1) "not" + safe (adj.).
- unsaturated (adj.)
- 1756, from un- (1) "not" + past participle of saturate (v.).
- unscrupulous (adj.)
- 1803, from un- (1) "not" + scrupulous (adj.). Related: Unscrupulously; unscrupulousness.
- unsupervised (adj.)
- 1845, from un- (1) "not" + past participle of supervise (v.).
- unstinted (adj.)
- late 15c., from un- (1) "not" + past participle of stint (v.).
- unsinkable (adj.)
- 1650s, from un- (1) "not" + sinkable (see sink (v.)).
- unsmiling (adj.)
- 1730, from un- (1) "not" + present participle of smile (v.).
- untroubled (adj.)
- late 15c., from un- (1) "not" + past participle of trouble (v.).
- untrodden (adj.)
- c. 1300, from un- (1) "not" + past participle of tread (v.).
- untried (adj.)
- 1510s, "not proven or tested," from un- (1) "not" + tried.
- unsuspected (adj.)
- 1520s, from un- (1) "not" + past participle of suspect (v.).
- unidentified (adj.)
- 1860, from un- (1) "not" + past participle of identify (v.).
- unimpeded (adj.)
- 1760, from un- (1) "not" + past participle of impede (v.).
- unintelligible (adj.)
- 1610s, "incapable of being understood," from un- (1) "not" + intelligible. Related: Unintelligibly.
- unabated (adj.)
- 1610s, from un- (1) "not" + past participle of abate (v.).
- unemotional (adj.)
- 1819, from un- (1) "not" + emotional (adj.). Related: Unemotionally.
- unexplained (adj.)
- 1721, from un- (1) "not" + past participle of explain (v.).
- unformed (adj.)
- early 14c., from un- (1) "not" + past participle adjective from form (v.).
- unfrequented (adj.)
- 1580s, from un- (1) "not" + past participle of frequent (v.).
- unlamented (adj.)
- 1590s, from un- (1) "not" + past participle of lament (v.).
- unmolested (adj.)
- 1530s, from un- (1) "not" + past participle of molest (v.).
- unmitigated (adj.)
- 1590s, from un- (1) "not" + past participle of mitigate (v.).
- unmatched (adj.)
- 1580s, "unrivaled," from un- (1) "not" + past participle of match (v.).
- unlivable (adj.)
- 1834, "incapable of being lived in," from un- (1) "not" + livable.
- unlimited (adj.)
- mid-15c., from un- (1) "not" + past participle of limit (v.).
- unnecessary (adj.)
- 1540s, from un- (1) "not" + necessary (adj.). Related: Unnecessarily.
- unobserved (adj.)
- 1610s, from un- (1) "not" + past participle of observe (v.).
- unobstructed (adj.)
- 1650s, from un- (1) "not" + past participle of obstruct (v.).
- unofficial (adj.)
- 1798, from un- (1) "not" + official (adj.). Related: Unofficially.
- unopposed (adj.)
- 1650s, from un- (1) "not" + past participle of oppose (v.).
- unchanged (adj.)
- late 14c., from un- (1) "not" + past participle of change (v.).
- undefeated (adj.)
- 1701, from un- (1) "not" + past participle of defeat (v.).
- undefined (adj.)
- 1610s, from un- (1) "not" + past participle of define (v.).
