early 15c., "not in accord with physical nature," from un- (1) "not" + natural (adj.). Meaning "artificial" is attested from 1746; that of "at variance with moral standards" is from 1520s. Related: Unnaturally; unnaturalness.

"alter (something) so as to change its nature," 1878, from French dénaturer (Old French desnaturer "change the nature of; make unnatural"); see de- + nature. Earlier it meant "to make unnatural" (1680s). Earlier in the modern sense of denature was denaturalize (1812). Related: Denatured.

1610s, "to go too far in action," from over- + act (v.). Meaning "play a part with too much emphasis, act (a part) with an extravagant and unnatural manner, chew the scenery" is from 1630s. Related: Overacted; overacting.

1550s, "ominous, portentous" (a sense now obsolete), from French prodigieux and directly from Latin prodigiosus "strange, wonderful, marvelous, unnatural," from prodigium "an omen, portent, monster" (see prodigy).

From 1560s as "causing wonder or amazement;" 1570s as "unnatural, abnormal." The meaning "vast, enormous, wonderfully large" is from c. 1600. As a pseudo-adverb, "exceedingly," by 1670s. Related: Prodigiously; prodigiousness; prodigiosity.

"one who practices gymnastic feats involving contorted or unnatural poses," 1841, from contortion + -ist.

Old English uncynde "unnatural, not natural;" see un- (1) "not" + kind (adj.). Meaning "lacking in kindness" is recorded from mid-14c.

early 13c., "not natural, unnatural," from un- (1) "not" + kindly (adj.). From c. 1300 as "without natural affection, unfraternally." Old English had ungecyndelic.

"not spontaneous or voluntary, strained, unnatural," 1570s, past-participle adjective from force (v.). Meaning "effected by an unusual application of force" is from 1590s. Related: Forcedly. The flier's forced landing attested by 1917.

early 15c., of food, "quality of producing unnatural humors," from Old French crudité (14c.) and directly from Latin cruditatem (nominative cruditas) "indigestion," from crudus "rough; not cooked, raw, bloody" (see crude). From 1620s as "that which is crude;" 1630s as "quality or state of being crude."

"deep, unnatural sleep; lethargy," 1670s; earlier in a figurative sense (1650s), from Latin sopor "deep sleep," from suffixed form of PIE root *swep- "to sleep," the source also of Latin somnus, Greek hypnos.