Search Result for "idiot savant":
Wordnet 3.0

NOUN (1)

1. person who is mentally retarded in general but who displays remarkable aptitude in some limited field (usually involving memory); 



WordNet (r) 3.0 (2006):

idiot savant
    n 1: person who is mentally retarded in general but who displays
         remarkable aptitude in some limited field (usually
         involving memory)