'boneheadedness' definitions:

Definition of 'boneheadedness'

From: GCIDE
  • boneheaded \bone"head*ed\ adj. very stupid; -- used of people or actions. [informal] -- {bone"head*ed*ness}, n.
  • Syn: blockheaded, fatheaded, loggerheaded, thick, thickheaded, thick-skulled, wooden-headed. [WordNet 1.5] bone-idle