From The Collaborative International Dictionary of English v.0.48 [gcide]:
Unintelligent \Unintelligent\
See intelligent.
From WordNet (r) 3.0 (2006) [wn]:
unintelligent
adj 1: lacking intelligence; "a dull job with lazy and
unintelligent co-workers" [syn: unintelligent,
stupid] [ant: intelligent]