Dunderhead

A person with no intelligence

Idiot,Plonker,Pillock,Klutz
Dunce,Numskull, Blockhead, Bonehead, Lunkhead, Hammerhead, Knucklehead,Muttonhead, Shithead,Fuckhead

''what you doing!'' ahh you dunderhead!''

Four eyes

(Facetious and Derogatory) Describing a person who looks stupid while wearing glasses

''hey four eyes should have been to specsavers!''

Bumhole

A stupid person ,the anus. Another way to call someone a arsehole,Asshole

''You stupid bumhole!''