Green’s Dictionary of Slang

dickhead adj.

also dickheaded
[dickhead n. (1)]

stupid, foolish.

[UK]K. Lette Llama Parlour 74: Then I did a really dickheaded thing.
[UK]D. Jarman diary 12 Feb. Smiling in Slow Motion (2000) 311: Comments from a dickhead Tory MP.
[UK]N. Barlay Curvy Lovebox 30: It’s only a matter of time before he hears about the dickhead brothers.
[UK]N. Griffiths Stump 49: Gozzy Squires an Lenny Reece an their dick’ed mates.
[US](con. 1960s) J. Ellroy Blood’s a Rover 20: Your story [...] is some fucking story compared to the other dickhead stories I heard lately.
[Aus] D. Whish-Wilson ‘In Savage Freedom’ in Crime Factory: Hard Labour [ebook] Dickhead hip-hop on the iPod dock.
[UK]Skepta ‘Crime Riddim’ [lyrics] You actually got nicked?Man, dickhead ting, fighting ting, famm.