Green’s Dictionary of Slang

(orig. US) a fool, an idiot; thus dumbfuckery, behaviour typical of such an individual.

1952		J. Jones From Here to Eternity (1998) 564: I know some dumb f-- treat a Jew mean, but not in our Company.
1972		G.V. Higgins Friends of Eddie Coyle 23: Arthur goes to jail. Dumb fuck.
1986		L. Heinemann Paco’s Story (1987) 23: Son-of-a-bitch, Jack, there were more dumb fucks in Bravo Company than anywhere.
1998		Sick Puppy Comix ((Sydney) #8 18: ‘It’s not a demon it’s nicotine you dumb fuck!’.
1999		Guardian Guide 31 July–6 Aug. 52: The dumb fucks don’t even know how to get their burning crosses to light.
2004		C. Hiaasen Skinny Dip 193: You’re one dumb fuck of a so-called doctor.
2005		A. Lovejoy Acid Alex 75: What the fuck were you doing with all that stuff in your locker you dumb cunt. [...] We agreed you stupid dumb fuck, that we would leave every fucking thing hidden away.
2010		A. Steinberg Running the Books 83: You dumb fuck.
2012		M. McBride Frank Sinatra in a Blender [ebook] Johnny, he’s behind us you dumbfuck!
2017		D. Winslow The Force [ebook] ‘You’d do that to me, Malone?’ ‘I’m doing it to you now, dumbfuck’.
2017		Twitter 5 Dec. 🌐 After 17 months of inexorable creep toward the dumbfuckery of Brexit I am no longer convinced that Brexit/Remain is even a meaningful dichotomy.