decease vs departure

decease and departure both are nouns.

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

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

decease (noun)	departure (noun)
the event of dying or departure from life	the act of departing
	euphemistic expressions for death
	a variation that deviates from the standard or norm

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