Green’s Dictionary of Slang

(US) contemptible, offensive, worthless; also as adv.

1939		in New Directions 138: Get down off that horseshit New York wise-guy stuff [HDAS].
1949		Kerouac letter 28 June in Charters Letters: 1940–56 207: These here brittle horseshit New York mannequins.
1962		(con. WWII) J.O. Killens And Then We Heard The Thunder (1964) 48: The horse-shit propaganda.
1971		B. Malamud Tenants (1972) 69: They all turned it down for a lot of horseshit reasons, because they are afraid of what the book says.
1977		Fidrych & Clark No Big Deal 93: I said, Oh, this is it, baseball’s over now. Five and ten record, ten complete games I’m doin’ horseshit! [ibid.] 107: I stepped on the mound, and like, I threw horseshit.
1987		G.A. Fine With the Boys 110: Would taste awful horseshit.
1991		(con. 1920s) O.D. Brooks Legs 198: The job is horseshit.
2000		Guardian Mag. 20 May 35: I had the standard horse-shit upbringing.
2003		Simon & Alvarez ‘Backwash’ Wire ser. 2 ep. 7 [TV script] I don’t stand around listening to horseshit excuses.
2013		F. Bill Donnybrook [ebook] Got [...] an officer laid up ’cause of your horseshit Dirty Harry way of handling things’.