Old English ut "out, without, outside," common Germanic (cf. Old Norse, Old Frisian, Old Saxon, Gothic ut, Middle Dutch uut, Dutch uit, Old High German uz, German aus), from PIE root *ud- "up, out, up away" (cf. Sanskrit ut "up, out," uttarah "higher, upper, later, northern;" Avestan uz- "up, out," Old Irish ud- "out," Latin usque "all the way to, without interruption," Greek hysteros "the latter," Russian vy- "out"). Meaning "into public notice" is from 1540s. As an adjective from c.1200. Meaning "unconscious" is attested from 1898, originally in boxing. Sense of "not popular or modern" is from 1966. As a preposition from mid-13c.
Sense in baseball (1860) was earlier in cricket (1746). Adverbial phrase out-and-out "thoroughly" is attested from early 14c.; adjective usage is attested from 1813; out-of-the-way (adj.) "remote, secluded" is attested from late 15c. Out-of-towner "one not from a certain place" is from 1911. Shakespeare's It out-herods Herod ("Hamlet") reflects Herod as stock braggart and bully in old religious drama and was widely imitated 19c. Out to lunch "insane" is student slang from 1955; out of this world "excellent" is from 1938; out of sight "excellent, superior" is from 1891.
Old English utian "expel, put out" (see out (adv.)); used in many senses over the years. Meaning "to expose as a closet homosexual" is first recorded 1990 (as an adjective meaning "openly avowing one's homosexuality" it dates from 1970s; see closet); sense of "disclose to public view, reveal, make known" has been present since mid-14c.
Eufrosyne preyde Þat god schulde not outen hire to nowiht. [Legendary of St. Euphrosyne, c.1350]Related: Outed; outing.
1620s, "a being out" (of something), from out (adv.). From 1860 in baseball sense; from 1919 as "means of escape; alibi."
To the point of surfeit or exhaustion: I'm coffeed out for the time being/ I don't want them to think I'm losered out (1990s+)
A way of escape; a plausible alibi or evasive course; let out: You have an out, though. You can talk (1919+)
: Some gay activists have undertaken a campaign of outing, exposing well-known people who are believed to be gay (late 1980s+)