expiration vs departure

expiration and departure both are nouns.

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

As nouns, expiration and departure are synonyms defined as:

Other synonyms of expiration include exit, going, loss, passing, release.

expiration (noun)	departure (noun)
the act of expelling air from the lungs	the act of departing
euphemistic expressions for death	euphemistic expressions for death
a coming to an end of a contract period	a variation that deviates from the standard or norm