Green’s Dictionary of Slang

satisfactory, fine, good.

1965		W.C. Anderson Adam M-1 234: Everything is A-okay. A bull’s-eye.
1971		L. Bangs in Psychotic Reactions (1988) 62: An A-OK example of what I’m talking about is ‘Give It To Me.’.
1974		(con. 1960s) R. Price Wanderers 200: That’s fucking A-OK because who wants to have to get married and have kids.
1978		R. Price Ladies’ Man (1985) 155: Donny was A-OK.
1978		S. King Stand (1990) 680: Everything would be A-OK.
1999		People (Sydney) 5 July 65/3: The holy humper - who’s got six sprogs - also reckons it’s A-OK for chicks to get down on their knees and pray before the bald-headed god of love.
2001		(con. 1964–8) J. Ellroy Cold Six Thousand 326: Trust A-OK. Parity better.
2001		K. Sampson Outlaws (ms.) 14: Perfectly ay-okay saying ‘I asked him’ the year before, but once they started getting older it was all the other thing.
2005		C. Buzzell My War (2006) 13: Anybody who starts a day off with a beer is A-OK in my book.
2023		(con. 1962) J. Ellroy Enchanters 48: Phil rated them A-OK.