Adjective
Having a thick skull; stupid.
Source: Webster's dictionarythick headed
I'm not hopeless, that's the problem. I'm too hopeful, if anything ... I'm so thick-headed it's taken me this long to give up on men, but I can't give up completely, you know? So I ... I channel all my hope into an idea, to someone who can't reject me because he isn't real! Shannon Hale
The trade of thick-headed Michael: eating, drinking, and idling. Dutch Proverb