rational
1 enlightened, intelligent, judicious, logical, lucid, realistic, reasonable, sagacious, sane, sensible, sound, wise
2 cerebral, cognitive, ratiocinative, reasoning, thinking
3 all there (informal) balanced, compos mentis, in one's right mind, lucid, normal, of sound mind, sane
Antonyms
insane, irrational, unreasonable, unsound