rigour vs cogency

rigour and cogency both are nouns.

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

As nouns, rigour and cogency are synonyms defined as:

Other synonyms of rigour include rigor, validity.

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