unconnected (adj.)
1736, from un- (1) "not" + past participle of connect (v.).
unconquerable (adj.)
1590s, from un- (1) "not" + conquer + -able.
unconscionable (adj.)
1560s, "showing no regard for conscience," from un- (1) + now rare conscionable "conscientious." Related: Unconscionably.
unconscious (adj.)
1712, "unaware, not marked by conscious thought," from un- (1) "not" + conscious. Meaning "temporarily insensible, knocked out" is recorded from 1860. Related: Unconsciously; unconsciousness. In psychology, the noun the unconscious (1876) is a loan-translation of German das Unbewusste. The adjective in this sense is recorded from 1912.
unconstitutional (adj.)
1734, from un- (1) "not" + constitutional (adj.). Related: Unconstitutionally.
unconstrained (adj.)
1640s, from un- (1) "not" + past participle of constrain (v.). Related: Unconstrainedly.
uncontested (adj.)
1670s, from un- (1) "not" + contested.
uncontrollable (adj.)
1570s, "irrefutable," from un- (1) "not" + controllable. From 1590s as "not subject to authority;" meaning "that cannot be restrained" is from 1640s. Related: Uncontrollably.
uncontrolled (adj.)
1510s, from un- (1) "not" + past participle of control (v.).
uncontroverted (adj.)
"not liable to be called into question," 1640s, from un- (1) "not" + past participle of controvert (v.).
unconventional (adj.)
1832, from un- (1) "not" + conventional (adj.). "A 19 cent. epithet for a certain type of affectation." [Weekley] Related: Unconventionally.
unconventionality (n.)
1849, with reference to Shelley, from unconventional + -ity.
unconverted (adj.)
1640s, from un- (1) "not" + past participle of convert (v.).
unconvinced (adj.)
1670s, from un- (1) "not" + past participle of convince (v.). Unconvincing is recorded from 1650s.
uncool (adj.)
1953, in hipster slang, from un- (1) "not" + slang sense of cool (adj.).
uncooperative (adj.)
also uncoöperative, 1847, from un- + cooperative (adj.). Related: Uncooperatively.
1801, from un- (1) "not" + past participle of coordinate (v.).
uncorrupted (adj.)
c.1400, of organic matter, "not putrefied," from un- (1) "not" + past participle of corrupt (v.). From 1560s of persons, "not influenced by bribes."
uncorruptible (adj.)
late 14c., from un- (1) "not" + corruptible (adj.).
uncountable (adj.)
late 14c., from un- (1) "not" + count (v.) + -able.
uncounted (adj.)
c.1500, from un- (1) "not" + past participle of count (v.).
uncouple (v.)
c.1300, from un- (2) "opposite of" + couple (v.). Similar formation in Middle Dutch ontcoppelen. Related: Uncoupled; uncoupling.
uncouth (adj.)
Old English uncuð "unknown, strange, unusual; uncertain, unfamiliar; unfriendly, unkind, rough," from un- (1) "not" + cuð "known, well-known," past participle of cunnan "to know" (see can (v.1)). Meaning "strange, crude, clumsy" is first recorded 1510s. The compound (and the thing it describes) widespread in IE languages, such as Latin ignorantem, Old Norse ukuðr, Gothic unkunþs, Sanskrit ajnatah, Armenian ancanaut', Greek agnotos, Old Irish ingnad "unknown."
uncover (v.)
early 14c., from un- (2) "reverse of" + cover (v.). Earliest use is figurative; literal sense is attested from late 14c. Related: Uncovered; uncovering.
uncredited (adj.)
1580s, from un- (1) "not" + past participle of credit (v.).
uncritical (adj.)
1650s, from un- (1) "not" + critical. Similar formation in Dutch onkritisch, German unkritisch, Danish unkritisk. Related: Uncritically.
unction (n.)
"act of anointing as a religious rite," late 14c., from Latin unctionem (nominative unctio) "anointing," from unctus, past participle of ungere "to anoint" (see unguent).
unctious (adj.)
common variant of unctuous c.1600-1725.
unctuous (adj.)
late 14c., "oily, having a greasy or soapy feeling when touched," from Old French unctueus, from Medieval Latin unctuosus "greasy," from Latin unctus "act of anointing," from past participle stem of unguere "to anoint" (see unguent).

Figurative sense of "blandly ingratiating" is first recorded 1742, perhaps in part with a literal sense, but in part a sarcastic usage from unction in the meaning "deep spiritual feeling" (1690s), such as comes from having been anointed in the rite of unction. Related: Unctuously; unctuousness.
uncultivated (adj.)
1640s (figurative); 1680s (of plants); 1690s (of land), from un- (1) "not" + past participle of cultivate (v.).
uncurbed (adj.)
1590s, from un- (1) "not" + past participle of curb (v.).
uncurious (adj.)
1560s, "not inquisitive," from un- (1) "not" + curious (adj.). From 1680s as "not odd or strange."
uncurl (v.)
1580s, intransitive; 1590s, transitive," from un- (2) "reverse, opposite of" + curl (v.).
uncut (adj.)
early 15c., "not gashed or wounded," from un- (1) "not" + past participle of cut (v.). Of books, "not having the leaves slit open" it is recorded from 1828; of plays, etc., "without excisions," it is attested from 1896.
undated (adj.)
"left without indication of date," 1560s, from un- (1) "not" + past participle of date (v.1) "assign a date to." Compare similarly formed German undatirt, Dutch ongedateerd, Swedish odaterad.
undaunted (adj.)
mid-15c., with reference to horses, "untamed, not broken in," from un- (1) "not" + past participle of daunt (v.). In reference to persons, "intrepid," it is recorded from 1580s.
undaunting (adj.)
1786, "not quailing" [OED], from un- (1) "not" + present participle of daunt (v.).
undead (adj.)
"neither dead nor alive," c.1400, from un- (1) "not" + dead. As a noun meaning "vampires and such," from 1904. Old English undeadlic (adv.) meant "immortal, for all eternity."
undeceive (v.)
"to free from deception," 1590s, from un- (2) "opposite of" + deceive (v.).
undeceived (adj.)
c.1400, "reliable, accurate, certain," from un- (1) "not" + past participle of deceive (v.).
undecennial (adj.)
"occurring every 11 years," 1858, in reference to solar activity cycle, from Latin undecim "eleven" + ending from biennial, etc.
undecided (adj.)
1530s, "not decided, unsettled," from un- (1) "not" + past participle of decide (v.).
undecipherable (adj.)
1758, from un- (1) "not" + decipherable (see decipher (v.)).
undecisive (adj.)
1660s, from un- (1) "not" + decisive. The usual word is indecisive.
undefeated (adj.)
1701, from un- (1) "not" + past participle of defeat (v.).
undefended (adj.)
1560s, "not defended, unprotected," from un- (1) "not" + past participle of defend (v.). Attested earlier in a now-obsolete sense of "unforbidden" (late 14c.).
undefiled (adj.)
c.1300, undefylde, from un- (1) "not" + past participle of defile (v.). Originally of morals; sexual sense is attested from mid-15c. Physical sense of "not made dirty" is from 1580s.
undefined (adj.)
1610s, from un- (1) "not" + past participle of define (v.).
undelivered (adj.)
late 15c., from un- (1) "not" + past participle of deliver (v.).
undemanding (adj.)
1879, from un- (1) "not" + demanding (adj.).