cogency vs rigor

cogency and rigor both are nouns.

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

As nouns, cogency and rigor are synonyms defined as:

Other synonyms of cogency include rigour, validity.

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