Green’s Dictionary of Slang

(US) having large buttocks, fat; thus lazy, useless.

1946		T. Heggen Mister Roberts xv: He is bow-legged and broad-beamed (for which the crew would substitute ‘lard-assed’).
1953		J. Thompson Criminal (1993) 55: All we’ve got to go on is [...] what that lardassed d.a. says.
1962		(con. 1940s) G. Mandel Wax Boom 306: You are a lard-assed fathead who sees Adonis in the mirror.
1971		L. Bangs in Psychotic Reactions (1988) 75: They don’t have as many protocols and taboos as those lard-ass beatniks.
1986		L. Heinemann Paco’s Story (1987) 77: Any half-bright, lard-assed nitwit who can comb hair can goddam cut hair in the Army.
2000		Observer Sport 12 Mar. 9: Several of the England players talked of looking at the lard-arsed Welsh and knowing the game was won.
2003		Bug (Aus.) June 🌐 Joey Johns to Ricketty Stuart: ‘You tell that lard-arse loser I have taken that advice on board.’.
2003		Mad mag. June 34: Sweaty, humongous, wide-bodied, lard-assed, fat students.
2004		T. Winton ‘Family’ in Turning (2005) 184: He played to prove every balding, wheezy lard-arse commentator wrong.
2009		T. Black Gutted 25: Unctuous, lardarse businessmen from Nowhere, Arkansas.