Green’s Dictionary of Slang

1. (also boffing) a strong blow.

1938		D. Runyon ‘A Piece of Pie’ in Runyon on Broadway (1954) 674: A boff on the beezer.
1946		D. Runyon ‘A Light in France’ from First to Last 66: Rudolph [...] has a notion to give her a good boffing. [Ibid.] 245: I quietly give Girondel a boff over his pimple with a blackjack.
1951		Green & Laurie Show Biz from Vaude to Video 567: Boff – a hit.
1969		‘Iceberg Slim’ Mama Black Widow 129: I got a boff on the head as I went by.

2. an act of sexual intercourse.

1962		S. Longstreet Flesh Peddlers (1964) 341: Twice a week a boff after Chinese food and a kid every three years.
1966		Trimble 5000 Adult Sex Words and Phrases.
1977		P. Hamill Flesh and Blood (1978) 203: Hell, I’d like to give you a boff, boy. Right in the ass. Bet you like it there, don’t you, boy?
1999		Guardian Rev. 16 July 8: There are a lot of great English terms for doing it – boff, or shag, or screw.
2002		J. Meades Fowler Family Business 78: Lots of scoff and lots of boff.

3. a person seen as an object of sexual intercourse.

1993

B. Moore Lex. of Cadet Lang. 49: usage What say we go to the Bin tonight and get ourselves a boff?