stupid
noun
a person who is not very bright
“The economy, stupid!”
adjective
lacking or marked by lack of intellectual acuity
Oppositessmartin a state of mental numbness especially as resulting from shock
“he had a dazed expression on his face”
“lay semiconscious, stunned (or stupefied) by the blow”
lacking intelligence
“a dull job with lazy and unintelligent co-workers”
Synonymsunintelligent
Source: WordNet 3.1, Princeton University
