simpleton

from WordNet (r) 3.0 (2006)

simpleton
    n 1: a person lacking intelligence or common sense [syn:
         {simpleton}, {simple}]

from The Collaborative International Dictionary of English v.0.48

Simpleton \Sim"ple*ton\, n. [Cf. F. simplet, It. semplicione.]
   A person of weak intellect; a silly person.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

26 Moby Thesaurus words for "simpleton":
      ament, born fool, bungler, clot, congenital idiot, cretin,
      defective, dullard, dullhead, dumbbell, dummkopf, dummy, golem,
      half-wit, idiot, ignoramus, imbecile, juggins, mongoloid idiot,
      moron, natural, natural idiot, natural-born fool, simp, stupid,
      zany

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