validity vs cogency

validity and cogency both are nouns.

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

As nouns, validity and cogency are synonyms defined as:

Other synonyms of validity include rigor, rigour.

validity (noun)	cogency (noun)
the quality of having legal force or effectiveness	the quality of being valid and rigorous
the quality of being valid and rigorous	persuasive relevance