pass away vs asphyxiate

pass away and asphyxiate both are verbs.

Word	Noun	Adjective	Verb	Adverb
pass away	No	No	Yes	No
asphyxiate	No	No	Yes	No

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

pass away: 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 pass away include abort, stifle, suffocate, buy it, pip out, drown, predecease, famish, starve, fall, succumb, yield.

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