impermanency vs impermanence

impermanency and impermanence both are nouns.

Word	Noun	Adjective	Verb	Adverb
impermanency	Yes	No	No	No
impermanence	Yes	No	No	No

As nouns, impermanency and impermanence are synonyms defined as:

impermanency and impermanence: the property of not existing for indefinitely long durations

impermanency (noun)	impermanence (noun)
the property of not existing for indefinitely long durations	the property of not existing for indefinitely long durations