pass away vs drown

pass away and drown both are verbs.

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

As verbs, drown is a hyponym of pass away; that is, drown 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
drown: die from being submerged in water, getting water into the lungs, and asphyxiating

Other hyponyms of pass away include abort, asphyxiate, stifle, suffocate, buy it, pip out, predecease, famish, starve, fall, succumb, yield.

pass away (verb)	drown (verb)
pass from physical life and lose all bodily attributes and functions necessary to sustain life	die from being submerged in water, getting water into the lungs, and asphyxiating
go out of existence	kill by submerging in water
	get rid of as if by submerging
	cover completely or make imperceptible
	be in danger of dying from submersion in a liquid and asphyxiation
	be covered with or submerged in a liquid