decease vs expiration

decease and expiration both are nouns.

Word	Noun	Adjective	Verb	Adverb
decease	Yes	No	Yes	No
expiration	Yes	No	No	No

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

decease (noun)	expiration (noun)
the event of dying or departure from life	the act of expelling air from the lungs
	euphemistic expressions for death
	a coming to an end of a contract period

decease (verb)	expiration (verb)
pass from physical life and lose all bodily attributes and functions necessary to sustain life