expiration vs decease

expiration and decease both are nouns.

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

As nouns, decease is a hypernym of expiration; that is, decease is a word with a broader meaning than expiration:

Other hypernyms of expiration include death, expiry.

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

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