relevance vs pertinency

relevance and pertinency both are nouns.

Word	Noun	Adjective	Verb	Adverb
relevance	Yes	No	No	No
pertinency	Yes	No	No	No

As nouns, pertinency is a hyponym of relevance; that is, pertinency is a word with a more specific, narrower meaning than relevance:

Other hyponyms of relevance include materiality, cogency, point, applicability, pertinence.

relevance (noun)	pertinency (noun)
the relation of something to the matter at hand	relevance by virtue of being applicable to the matter at hand