expiry vs modification

expiry and modification both are nouns.

Word	Noun	Adjective	Verb	Adverb
expiry	Yes	No	No	No
modification	Yes	No	No	No

As nouns, modification is a hypernym of expiry; that is, modification is a word with a broader meaning than expiry:

expiry: the event of dying or departure from life
modification: an event that occurs when something passes from one state or phase to another

Other hypernyms of expiry include alteration, change.

expiry (noun)	modification (noun)
the event of dying or departure from life	the act of making something different (as e.g. the size of a garment)
a coming to an end of a contract period	slightly modified copy; not an exact copy
	an event that occurs when something passes from one state or phase to another
	the grammatical relation that exists when a word qualifies the meaning of the phrase