Green’s Dictionary of Slang

a very fat person; also as a term of address.

[1672		J. Howard All Mistaken V i: Why my most Extream Fat Asse, dost thou not find that I have fool’d thee All this while?].
c.1900		‘Ramrod’ Nocturnal Meeting 58: His usual term of endearment for me is ‘fat-arse or split-arse little fucker’.
1923		D.H. Lawrence Kangaroo 364: Look at ’em, and you’ll see they’ve got good, heavy-weight sit-upons [...] Greedy fat-arses, mates if you’ll pardon the vulgarity for once. Greedy fat-arses.
1931		J.T. Farrell ‘Big Jeff’ in Short Stories (1937) 46: Jeff the fatass of Fifty-eighth Street.
1938		‘Justinian’ Americana Sexualis 21: Fatass, n. A broad-buttocked person, generally a woman.
1945		J.B. Priestly Three Men in New Suits 56: Little Lizzie Fat-bum there is off to Canada soon.
1962		B. McGhee Cut and Run (1963) 157: ‘A minute, Fat-ass,’ he shouted, waving his open razor.
1966		F. Elli Riot (1967) 101: How’d you get in the gang, fat-arse?
1969		D. Pendleton Executioner (1973) 389: I could’ve plowed a furrow right up fat-ass’s behind.
1970		E. Thompson Garden of Sand (1981) 171: I knew that if fatass could get his gun out of the cash register he might of hurt somebody.
1970		H.E. Bates A Little of What You Fancy (1985) 484: ‘Yes!’ Pop shouted. ‘You old fat arse.’.
1977		L. Heinemann Close Quarters (1987) 13: Hey, Fatboy? How much you weigh, Fat-ass?
1979		‘Iceberg Slim’ Airtight Willie and Me 97: Fatass, if you blink your eyes I’ll blow your head into your lap.
1989		H. Rawson Dict. of Invective (1991) 144: fat ass. A broad-beamed person.
2000		‘Case SC94004’ Appeal on Florida Courts 🌐 You’re going to get your fat ass picked up because they’re hot as hell.
2005		J. Stahl I, Fatty 43: ‘Hey, fat-ass?’.