1. (a.) Relating to the reason; not physical; mental.

2. (a.) Having reason, or the faculty of reasoning; endowed with reason or understanding; reasoning.

3. (a.) Agreeable to reason; not absurd, preposterous, extravagant, foolish, fanciful, or the like; wise; judicious; as, rational conduct; a rational man.

4. (a.) Expressing the type, structure, relations, and reactions of a compound; graphic; -- said of formulae. See under Formula.

5. (n.) A rational being.

acceptable admissible algorismic algorithmic aliquot all there analytic balanced bright calm cardinal cerebral circumspect clear-eyed clearheaded clearminded cogent commonsense compos mentis conceptive conceptual consequent cool coolheaded credible decimal differential digital discriminating discursive down-to-earth earthy endopsychic enlightened even everyday exponential figural figurate figurative finite fractional hardheaded healthy-minded ideational imaginary impair impossible infinite informed integral intellectual intelligent internal irrational judicious just justifiable knowing knowledgeable legitimate level-headed levelheaded logarithmic logical logometric lucid matter-of-fact mental mentally sound negative noetic noological normal not so dumb numeral numerary numerative numeric odd of sound mind ordinal pair philosophical phrenic plausible positive positivistic possible practical practical-minded pragmatic prime prudent psychic psychologic radical ratiocinative ratiocinatory real realist realistic reasonable reasoning reciprocal right sane sane-minded scientific scientistic secular sensible sober sober-minded sophic sound sound-minded sound-thinking spiritual stable straight-thinking strong-minded subjective submultiple surd thinking together transcendental understanding unideal unidealistic unromantic unsentimental well-argued well-balanced well-founded well-grounded wholesome wise worldly