sanity vs rationality

sanity and rationality both are nouns.

Word	Noun	Adjective	Verb	Adverb
sanity	Yes	No	No	No
rationality	Yes	No	No	No

As nouns, rationality is a hyponym of sanity; that is, rationality is a word with a more specific, narrower meaning than sanity:

Other hyponyms of sanity include lucidity, reason, reasonableness.

sanity (noun)	rationality (noun)
normal or sound powers of mind	the quality of being consistent with or based on logic
	the state of having good sense and sound judgment