simple-minded

from WordNet (r) 3.0 (2006)

simple-minded
    adj 1: lacking subtlety and insight; "a simple-minded argument"
    2: lacking mental capacity and subtlety [syn: {dim-witted},
       {simple}, {simple-minded}]

from The Collaborative International Dictionary of English v.0.48

Simple-minded \Sim"ple-mind`ed\, a.
   Artless; guileless; simple-hearted; undesigning;
   unsuspecting; devoid of duplicity. --Blackstone. --
   {Sim"ple-mind`ed*ness}, n.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

65 Moby Thesaurus words for "simpleminded":
      arrested, artless, babbling, backward, blithering, bluff, blunt,
      born yesterday, burbling, candid, childlike, confiding,
      crackbrained, cracked, crazy, cretinistic, cretinous, dim-witted,
      direct, dithering, driveling, drooling, dull, feebleminded, frank,
      guileless, half-baked, half-witted, idiotic, imbecile, imbecilic,
      ingenu, ingenuous, innocent, maundering, mentally defective,
      mentally deficient, mentally handicapped, mentally retarded,
      mongoloid, moronic, naive, not all there, open, openhearted,
      outspoken, plain, retarded, simple, simplehearted, simpletonian,
      sincere, single-hearted, single-minded, slobbering, slow,
      slow-witted, subnormal, trustful, trusting, unguarded, unreserved,
      unsophisticated, unsuspicious, unwary