Green’s Dictionary of Slang

shithead adj.

also shitheaded
[shithead n.]

an abusive epithet.

N. Mailer letter 20 Mar. in Selected Letters (2014) 238: I kept telling myself [...] that you weren’t a shithead snob like all the others.
[UK]Oz 8 40/3: Johnson and his shithead aides are murderous bullies.
[Aus]Tharunka (Sydney) 8 Nov. 27/2: ‘You shithead good for fuck-all-illiterate-prick’.
[US]G.V. Higgins Patriot Game (1985) 225: It ain’t funny, shithead darling brother.
[US]C. Hiaasen Tourist Season (1987) 262: That crazy-cretinous-brainless-shitheaded putz of a Cuban.
[Aus]R. Fitzgerald Pushed from the Wings (1989) 41: You’re the shit-head commentator who said my carer was over.
[US]W.T. Vollmann You Bright and Risen Angels (1988) 240: You shithead deck swabber.
[US](con. 1968) Bunch & Cole Reckoning for Kings (1989) 301: That shithead major didn’t ask me if I wanted to come along.
[Aus]P. Temple Broken Shore (2007) [ebook] The smartarses who walk [...] Outside, it’s the high fives. How easy was that. Fucking shithead cops, let’s do it again.