rigour vs validity

rigour and validity both are nouns.

Word	Noun	Adjective	Verb	Adverb
rigour	Yes	No	No	No
validity	Yes	No	No	No

As nouns, rigour and validity are synonyms defined as:

Other synonyms of rigour include cogency, rigor.

rigour (noun)	validity (noun)
something hard to endure	the quality of having legal force or effectiveness
the quality of being valid and rigorous	the quality of being valid and rigorous
excessive sternness