leave vs pass away

leave is a noun but pass away is not a noun.

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

leave (noun)	pass away (noun)
the act of departing politely
permission to do something
the period of time during which you are absent from work or duty

leave (verb)	pass away (verb)
leave unchanged or undisturbed or refrain from taking	pass from physical life and lose all bodily attributes and functions necessary to sustain life
be survived by after one's death	go out of existence
leave behind unintentionally
go and leave behind, either intentionally or by neglect or forgetfulness
move out of or depart from
go away from a place
leave or give by will after one's death
transmit (knowledge or skills)
put into the care or protection of someone
remove oneself from an association with or participation in
produce as a result or residue
make a possibility or provide opportunity for; permit to be attainable or cause to remain
act or be so as to become in a specified state
have left or have as a remainder