expiration vs huffing

expiration and huffing both are nouns.

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

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

Other hyponyms of expiration include puffing, snorting, blow, puff, wind.

expiration (noun)	huffing (noun)
the act of expelling air from the lungs	an act of forcible exhalation
euphemistic expressions for death
a coming to an end of a contract period