Green’s Dictionary of Slang

shitface n.1

[shit n. (1a) + -face sfx]

an unpleasant, distasteful person (occas. object); also directly as term of abuse; occas. adj.

[UK]K. Amis letter 19 Apr. in Leader (2000) 466: Wasn’t John’s first poem frightful? I wanted to take out my pencil and scrawl could of told you that, shitface across it.
[Aus]Tharunka (Sydney) 8 Nov. 27/1: ‘Who do you think you are, shit face?’.
[UK]W. Donaldson Balloons in Black Bag 169: ‘shit face!’ I shouted.
[US]T. Wolfe Bonfire of the Vanities 42: Yo! Shitface!
[UK]N. Barlay Curvy Lovebox 10: Grippin’ the handle of the slide like it was the throat of a shitface enemy.
[UK]K. Waterhouse Soho 54: All right, shitface, when are you going to review my last fucking novel?
[Aus]R. Hughes Things I Didn’t Know (2007) 116: Whatcha call yerself, shitface!
[US]Chicago Trib. 17 May TAB-6/1: He also referred to the pothole by [...] dergatory names [...] shit-face, wheel-whore, and stupidf asshole.