adj. 25B6; adjective
a rational approach : LOGICAL, reasoned, sensible, reasonable, cogent, intelligent, judicious, shrewd, common-sense, commonsensical, sound, prudent; down-to-earth, practical, pragmatic.
she was not rational at the time of signing : SANE, compos mentis, in one's right mind, of sound mind; normal, balanced, lucid, coherent; informal all there.
man is a rational being : INTELLIGENT, thinking, reasoning; cerebral, logical, analytical; formal ratiocinative.
illogical, insane.