[1] : The Collaborative International Dictionary of English v.0.48

moron \moron"\ m-or=on", n.; sp. pl. morones. sp.
   an inferior olive size having a woody pulp and a large
   clingstone pit, growing in the mountainous and high-valley
   districts around the city of moron, in spain.
   webster 1913 suppl.
see also:
morones 

[2] : The Collaborative International Dictionary of English v.0.48

moron \mo"ron\ m=o"ro^n, n. gr. mw^ros foolish, stupid.
   1. pedagogy a mentally retarded person whose intellectual
      development proceeds normally up to about the eighth year
      of age and is then arrested so that there is little or no
      further development; an adult having the mental
      development of an 8-to-12-year old. a moron is considered
      capable of doing routine work under supervision.
      webster 1913 suppl. +pjc

   2. hence, a very stupid person. informal, derogatory
      pjc -- moron"ic adj. -- moron"ically adv. --
      mo"ronism n. -- moron"ity n.
see also:
moron"ic moron"ically mo"ronism moron"ity 

[3] : WordNet (r) 2.0

moron
     n : a person of subnormal intelligence syn: idiot, imbecile,
          cretin, changeling, half-wit, retard
see also:
idiot imbecile cretin changeling half-wit retard 

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

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

Moron >> M Words
Moron, definition of term: Moron
moron_pag1.html