perseverance vs persistency

perseverance and persistency both are nouns.

Word	Noun	Adjective	Verb	Adverb
perseverance	Yes	No	No	No
persistency	Yes	No	No	No

As nouns, perseverance and persistency are synonyms defined as:

Other synonyms of perseverance include doggedness, persistence, pertinacity, tenaciousness, tenacity.

perseverance (noun)	persistency (noun)
the act of persisting or persevering; continuing or repeating behavior	persistent determination
persistent determination