adjective
1.
Synonyms: rational , consequent, logical, reasonable, sensible, sound
Contrasted words: irrational, unreasonable
Antonyms: unintelligent
2.
mentally keen or quick
quite intelligent for his age
Synonyms: alert, brainy, bright, brilliant, clever, knowing, knowledgeable, quick-witted, ready-witted, sharp, smart; compare wise 4
Related Word: astute, perspicacious, sagacious, shrewd; acute, keen; adroit, cunning, ingenious
Contrasted words: foolish, idiotic, imbecilic, moronic; crass, dense, dull, dumb, slow, stupid
Antonyms: unintelligent