rational

¹ra·tio·nal

adj \ˈrash-nəl, ˈra-shə-n^əl\

Definition of RATIONAL

1

a : having reason or understanding b : relating to, based on, or agreeable to reason : reasonable <a rational explanation> <rational behavior>

2

: involving only multiplication, division, addition, and subtraction and only a finite number of times

3

: relating to, consisting of, or being one or more rational numbers <a rational root of an equation>

— ra·tio·nal·ly adverb

— ra·tio·nal·ness noun

Examples of RATIONAL

1. <human beings are rational creatures>
2. <insisted there was a rational explanation for the strange creaking noises and that there were no such things as ghosts>

Origin of RATIONAL

Middle English racional, from Anglo-French racionel, from Latin rationalis, from ration-, ratio

First Known Use: 14th century

Related to RATIONAL

Synonyms: intelligent, reasonable, reasoning, thinking

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

Related Words: analytic (or analytical), logical; brainy, cerebral, highbrow, highbrowed, intellectual; cognitional, cognitive, mental; levelheaded, practical, sane, sensible, sober

Near Antonyms: brainless, dense, doltish, dopey (also dopy), dorky [slang], dull, dumb, fatuous, half-witted, mindless, obtuse, senseless, slow, stupid, thickheaded; fallacious, groundless, illogical, invalid, nonsensical

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Rhymes with RATIONAL

national, passional