Green’s Dictionary of Slang

1. (also noncomp) eccentric, crazy; thus compos adj.

1628		Coke On Littleton 247: So it is of a Non compos, and so it is of him qui gaudet lucidis interuallis [OED].
1695		Congreve Love for Love IV i: sir sampson: Mad! buckram: What, is he non compos? jeremy: Quite non compos, sir.
1702		Farquhar Twin-Rivals V i: They must find him non compos. He was mad before, you know.
1771		Smollett Humphrey Clinker (1925) I 193: The templar affirmed, that the poor fellow was non compos, and exhorted the justice to discharge him as a lunatic.
1828		J. Thomson An Uncle Too Many I ii: Only a little non compos, – rather cracked, or so.
1842		S. Lover Handy Andy 323: Tell me the worst at once, – is she non compos?
1861		H.C. Pennell Puck on Pegasus 19: Tho’ I write such utter twaddle, ’tis not from a non comp. noddle.
1887		Salt Lake Herald (UT) 9 Oct. 11/2: Maybe you wouldn’t object to having me locked up in an asylum [...] Well [...] you’re too late. You can’t get evidence now [...] that I am non compos.
1894		Hawaiian Gaz. 3 Aug. 6/1: The question whether under out statutes a person non compos may [...] maintain a libel for divorce.
1903		Brownsville Dly Herald (TX) 27 Apr. 3/2: The poor fellow is evidently non compos.
1909		J. Ware Passing Eng. of the Victorian Era.
1923		Wodehouse Leave it to Psmith (1993) 446: I think the boy’s noncompos.
1949		Wodehouse Mating Season 109: The man’s non compos.

2. used of an object, out of order, in a mess.

1921

Coconino Sun (Flagstaff, AZ) 28 Oct. 12/3: Fifteen years ago [...] Paul Kellor lost his gold watch. This week, Captain J.B. Wright [...] found it [...] The works are entirely non compos, but the case is as good as ever.

3. (also non-com) drunk .

1700		Congreve Way of the World V ii: My nephew was non compos, and could not make his addresses.
1737		B. Franklin ‘Drinkers Dict.’ in Pennsylvania Gazette 6 Jan. in AS XII:2 90: They come to be well understood to signify plainly that A MAN IS DRUNK. [...] Non Compos.
1804		C.L. Lewes Comic Sketches 26: The Beau would say he was, ‘Hocus, Non se ipse, Elevated, Electrified, or, Non Compos Mentis’.
1827		J. Wight More Mornings in Bow St. 70: Tatham came to the tavern, evidently rather non compos.
1831		Satirist (London) 24 July 125/3: Elliston [...] made, it is known, frequent sacrifices at Bacchus’ shrine and was not unusually ‘non compos’ ere noon.
1838		J.C. Neal Charcoal Sketches (1865) 109: He was in disgrace for a week, and always laboured under the imputation of having been a little non-com on that occasion.
1840		Marryat Poor Jack 4: Some people may infer from this, that he was at the time tipsy; he never told me so; all he said was , ‘Why, Jack, the fact is when they picked me up I was quite altogether “non pompus” [sic]’.
1850		(con. 1843) Melville White-Jacket (1990) 230: Taking care meanwhile to reel about very industriously, so that there shall be no doubt about their being seriously intoxicated, and altogether non compos.
1999		G. Seal Lingo 134: The effects of our occasionally over-enthusiastic imbibing show a great variety of invention and colour, including: [...] non compus; off your face; on the tiles; paralytic.
2007		S. Maloney Sucked In 202: Barry took the books off Merv when he was non-compos.

4. (Aus.) unconscious.

1977

(con. 1941) R. Beilby Gunner 213: ‘She did take your pants off after you’d flaked out again.’ ‘Did she, by God! It’s as well I was non compos.’.