Green’s Dictionary of Slang

1. (also fucking-aye!) an excl. generally used for emphasis, absolutely! definitely!

1964		Poston ‘Problems in the Study of Campus Sl.’ in AS XXXIX:2 116: Recently, fucking-A, an expression indicating total and complete assent, has become common.
1972		(con. 1950s) Jacobs & Casey Grease [play script] I i: Friggin’-A!
1974		(con. 1960s) R. Price Wanderers 203: ‘His nose split open like a tomato.’ Perry spat a small ball of saliva. [...] ‘Fuckin' A’.
1989		C. Hiaasen Skin Tight 97: ‘Fucking A,’ Chemo said. ‘We had a deal.’.
1992		G. Disher Paydirt [ebook] ‘Fuckin’ A [...] if I fuck up you’ll waste me’.
1992		G.P. Pelecanos Firing Offense 130: ‘You’ve been out here all afternoon?’ ‘Fuckin’ aye,’ he said.
1993		Tarantino & Avery Pulp Fiction [film script] 3: Fuckin’ A it worked [...] !
1995		J. Stahl Permanent Midnight 152: Dope fiends don’t piss themselves like winos. Fuckin’ aye!
1999		Observer Mag. 1 Aug. 31: I would get to New York as soon as possible, and fuckin’ A, I was gonna go.
2003		T. Dorsey Stingray Shuffle 66: ‘You’re really into this history stuff, aren’t you?’ [...] ‘Fuckin’-A.’.
2016		T. Robinson Rough Trade [ebook] ‘Are we the Avengers?’ Twitch smiled. ‘Fucking A’.
2020		D. Winslow ‘The San Diego Zoo’ in Broken 162: ‘You’re that cop! The Monkey Man!’ ‘Fuckin’ A,’ Chris says.

2. an excl. used to denote astonishment, dismay, acceptance, praise, recognition.

1981		J. Ellroy Brown’s Requiem 42: ‘Fucking A!’ Fat Dog said. I could feel him getting keyed up.
1987		(con. 1968) Bunch & Cole Reckoning for Kings (1989) 290: ‘Fuckin’ A!’ This was said in total awe.
1993		T. Jones Pugilist at Rest 105: Fucking-A. She’s got you pussy-whipped.
2001		‘Randy Everhard’ Tattoo of a Naked Lady 37: The Banana Boat! Fuckin-A!