Open English Wordnet
Nouns
Adjectives
(a)rationalconsistent with or based on or using reason“rational behavior”,
“a process of rational inference”,
“rational thought” (s)intellectual, rational, noeticof or associated with or requiring the use of the mind“intellectual problems”,
“the triumph of the rational over the animal side of man” (a)rationalcapable of being expressed as a quotient of integers“rational numbers” (s)rationalhaving its source in or being guided by the intellect (as distinguished from experience or emotion)“a rational analysis” 