cogency vs rigour

cogency and rigour both are nouns.

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

As nouns, cogency and rigour are synonyms defined as:

Other synonyms of cogency include rigor, validity.

cogency (noun)	rigour (noun)
the quality of being valid and rigorous	something hard to endure
persuasive relevance	the quality of being valid and rigorous
	excessive sternness