dim-witted

from WordNet (r) 3.0 (2006)

dim-witted
    adj 1: lacking mental capacity and subtlety [syn: {dim-witted},
           {simple}, {simple-minded}]

from The Collaborative International Dictionary of English v.0.48

dim-witted \dim-witted\ adj.
   mentally retarded; relatively slow in mental function.

   Syn: half-witted, simple, simple-minded.
        [WordNet 1.5 +PJC] Dimya