Entry Word: rational

Function: adjective

Meaning: 1 having the ability to reason <human beings are rational creatures>

Synonyms intelligent, reasonable, reasoning, thinking

Related Words analytic (or analytical), logical; brainy, cerebral, highbrow, intellectual; cognitive, mental; practical, sane, sensible

Near Antonyms brainless, mindless, stupid; illogical

Antonyms irrational, nonrational, unintelligent, unreasonable, unreasoning, unthinking

2 according to the rules of logic <insisted there was a rational explanation for the strange creaking noises and that there were no such things as ghosts> — see logical 1
3 based on sound reasoning or information <taking all your money out of your savings account and hiding it in a sock is not a rational move> — see good 1