numskull

from WordNet (r) 3.0 (2006)

numskull
    n 1: a stupid person; these words are used to express a low
         opinion of someone's intelligence [syn: {dunce},
         {dunderhead}, {numskull}, {blockhead}, {bonehead},
         {lunkhead}, {hammerhead}, {knucklehead}, {loggerhead},
         {muttonhead}, {shithead}, {dumbass}, {fuckhead}]

from The Collaborative International Dictionary of English v.0.48

Numskull \Num"skull`\, n. [Numb + skull.]
   A dunce; a dolt; a stupid fellow. [Also spelled {numbskull}.]
   [Colloq.]
   [1913 Webster]

         They have talked like numskulls.         --Arbuthnot.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

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

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