go away vs pass off

go away and pass off both are verbs.

Word	Noun	Adjective	Verb	Adverb
go away	No	No	Yes	No
pass off	No	No	Yes	No

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

go away (verb)	pass off (verb)
get lost, as without warning or explanation	expel (gases or odors)
go away from a place	come to pass
move away from a place into another direction	disappear gradually
become invisible or unnoticeable	disregard
	cause to be circulated and accepted in a false character or identity
	be accepted as something or somebody in a false character or identity