doof, n.¹ — Green’s Dictionary of Slang

doof n.¹

[abbr. dooflus n., but note Scot. doof, a dull, stupid person; ? ult. Ger. doof, dense, stupid, dull-witted]

(US) a fool, a simpleton.

1971		Current Sl. V:4 10: Doof, n. A bumbling fool; idiot.
1987		G.A. Fine With the Boys 169: Doof, n. Foolish awkward boy.
1995		X-Files 1 Dec. [TV script] Agent Pendrell: [grinning] ‘Hey, thanks. Keep it up yourself!’ [Scully looks at him strangely before leaving] Agent Pendrell: ‘Keep it up yourself... what a doof...’.
2002		Pifratco Files 🌐 All I can smell is the fiddly girly potpourri that JC bought for me recently. He’s such a doof when it comes to choosing gifts.
2006		D. Winslow Winter of Frankie Machine (2007) 41: He can smell the reefer, so now he knows he’s dealing with complete doofs.
2012		C. Eble (ed.) UNC-CH Campus Sl. 2011 3: DOOF — someone who is unknowingly amusing.