Green’s Dictionary of Slang

a phr. used to imply that somebody is very stupid; a general insult.

1960		(con. 1940s) D. MacCuish Do Not Go Gentle (1962) 145: Larko’s got shit fer brains.
[1964		J. Thompson Pop. 1280 in Four Novels (1983) 475: That stinking pile of crap you call brains!].
1967		M. Braly On the Yard (2002) 279: Doesn’t anything seep through that shit you have for brains?
1971		L. Bangs in Psychotic Reactions (1988) 7: If somebody did something stupid, we used to say, ‘Whattaya got, shit for brains?’.
1977		L. Heinemann Close Quarters (1987) 266: Has this dude ever got shit for brains.
1989		C. Hiaasen Skin Tight 252: You know what you’d find . . . Shit for brains, that’s what.
1994		Dly Press (Newport News, VA) 3 June 4/1: Unless you have poop for brains, you don’t waste a reporter’s time.
1998		J. O’Connor Salesman 241: Very careless lad, the Pony. Shite for brains, Homer.
2000		R.G. Barrett Leaving Bondi (2013) [ebook] [A]nybody that would invest money in a clunker like Leaving Bondi would have shit for brains.
2001		Guardian 10 Feb. 64/1: Mickey has [...] ‘shit for brains’.
2001		T. Fontana ‘Blizzard of ’01’ Oz ser. 4 ep. 13 [TV script] You got shit for brains.
2003		N. Griffiths Stump 169: They’re all stupid thick cunts, like. Can’t fuckin read or write [...] Shit-fer-brains.
2004		Morn. Star (Vernon, BC) 9 May 58/3: Does [...] a man who once made good movies [...] have poop for brains, agreeing to direct something that stinks so bad?
2012		N. Pettigrew ‘Wakey Wake’ in ThugLit Dec. [ebook] ‘Man, you got shit for brains’.
2019		C. Hammer Silver [ebook] Royce has shit for brains. He tried to sell some eccies [...] in the hostel.