rational number vs rational

rational number and rational both are nouns.

Word	Noun	Adjective	Verb	Adverb
rational number	Yes	No	No	No
rational	Yes	Yes	No	No

As nouns, rational number and rational are synonyms defined as:

rational number (noun)	rational (noun)
an integer or a fraction	an integer or a fraction

rational number (adjective)	rational (adjective)
	consistent with or based on or using reason
	capable of being expressed as a quotient of integers
	having its source in or being guided by the intellect (as distinguished from experience or emotion)
	of or associated with or requiring the use of the mind