[1] : WordNet (r) 2.0

dimwit
     n : a stupid incompetent person syn: nitwit, half-wit, doofus
see also:
nitwit half-wit doofus 

[2] : Moby Thesaurus II by Grady Ward, 1.0

30 moby thesaurus words for "dimwit":
   boeotian, block, clod, cluck, dolt, donkey, dope, dullard, dumb,
   dumb cluck, dumbbell, dummy, dunce, gowk, jobbernowl, lackwit,
   lamebrain, lightweight, looby, loon, niais, nincompoop, ninny,
   ninnyhammer, nitwit, noddy, put, stupid, thickwit, witling

Dimwit >> D Words
Dimwit, definition of term: Dimwit
dimwit_pag1.html