expire vs asphyxiate

expire and asphyxiate both are verbs.

Word	Noun	Adjective	Verb	Adverb
expire	No	No	Yes	No
asphyxiate	No	No	Yes	No

As verbs, asphyxiate is a hyponym of expire; that is, asphyxiate is a word with a more specific, narrower meaning than expire:

expire: pass from physical life and lose all bodily attributes and functions necessary to sustain life
asphyxiate: be asphyxiated; die from lack of oxygen

Other hyponyms of expire include abort, stifle, suffocate, buy it, pip out, drown, predecease, famish, starve, fall, succumb, yield.

expire (verb)	asphyxiate (verb)
expel air	be asphyxiated; die from lack of oxygen
pass from physical life and lose all bodily attributes and functions necessary to sustain life	deprive of oxygen and prevent from breathing
lose validity	impair the respiration of or obstruct the air passage of