Dunderhead \Dun"der*head`\, n. [Prov. Eng. also dunderpoll, from dunder, same as thunder.]

A dunce; a numskull; a blockhead. --Beau. & Fl. [1913 Webster]

Source: The Collaborative International Dictionary of English v.0.48
 

44 Moby Thesaurus words for "dunderhead": addlebrain, addlehead, addlepate, beefhead, blockhead, blubberhead, blunderhead, bonehead, bufflehead, cabbagehead, chowderhead, chucklehead, clodhead, clodpate, clodpoll, dolthead, dope, dullhead, dumbhead, dunderpate, fathead, jolterhead, jughead, knucklehead, lunkhead, meathead, muddlehead, mushhead, muttonhead, noddy, noodle, noodlehead, numskull, peabrain, pinbrain, pinhead, puddinghead, pumpkin head, puzzlehead, stupe, stupidhead, thickhead, thickskull, tottyhead

Source: Moby Thesaurus II by Grady Ward, 1.0
 

dunderhead

Source: WordNet (r) 2.0
 

Dunderhead \Dun"der*head`\, n. [Prov. Eng. also dunderpoll, from dunder, same as thunder.]

A dunce; a numskull; a blockhead. --Beau. & Fl.

Source: Webster's Revised Unabridged Dictionary (1913)