Green’s Dictionary of Slang

1. (also bull-skater) a braggart, a liar.

1927		(con. 1925) ‘J.H. Ross’ Mint (1955) 192: The airman at Cadet College who dared try for excellence at drill was a bull-shitter, a bobber, a creeping cunt.
1942		W. Winchell On Broadway 19 July. [synd. col.] The best line is mouthed by one of the bull-skaters trying to squelch the other with a bet.
1949		Kerouac letter 24 June in Charters I (1995) 200: Oh balls. I’m a bigger bullshitter than any of them.
1957		J. Gelber Connection 44: No square bullshitter is going to change me. [Ibid.] 87: And him coming on like he was the great artist of something or other. Bullshitter.
1963		C. Wood ‘Prisoner and Escort’ in Cockade (1965) I iii: You was one of the biggest bullshitters in the regiment.
1973		E. Bunker No Beast So Fierce 145: ‘Man, I don’t fuck around.’ ‘Good, good. I didn’t think you were a bullshitter.’.
1977		Maledicta 1 (Summer) 14: If he is fundamentally dishonest and a liar to boot, he’s a bullshitter, or a bullshit artist (B.A.).
1986		B. Geldof Is That It? 135: He was a terrible bullshitter, but the more bullshit he expended the more effective he was.
1996		J. Byrell Lairs, Urgers & Coat-Tuggers 881: The very same blasé bullshitter will also be prepared to blithely swear on a stack of Guinness Record Books that he even has trouble remembering that time he drew three to fill a royal routine.
1998		G. Burn Happy Like Murderers 213: A likeable kind of bullshitter is what he was.
2004		C. Hiaasen Skinny Dip 222: Chaz considered himself a master bullshitter.
2012		(con. 1980s) I. Welsh Skagboys 452: The cunt’s a bullshitter. Made maist ay that up.
2012		‘Dutch’ ? (Pronounced Que) [ebook] You can’t bullshit a bullshitter [...] I’m a lawyer, remember?
2020		C. Hiaasen Squeeze Me 233: ‘Please don’t bullshit me, Mr Tile.’ ‘Young lady, do I look like a bullshitter’.
2022		R. Stewart in Men’s Health July n.p.: [on B. Johnson] A liar is aware of the truth and misleads; a bullshitter doesn’t mind what the truth is [...] He has no moral framework .

2. the mouth.

1945		in Randolph & Legman Ozark Folksongs and Folklore (1992) I 549: ‘Milk-sucker, Chin-wiper, Bull-shiter, / Snot-catcher, Eye blinker, Ticky-box’.
1992		Randolph & Legman Ozark Folksongs and Folklore I 549: Bull-shitter, the mouth.