belch vs pass off

belch is a noun but pass off is not a noun.

Word	Noun	Adjective	Verb	Adverb
belch	Yes	No	Yes	No
pass off	No	No	Yes	No

As verbs, pass off is a hypernym of belch; that is, pass off is a word with a broader meaning than belch:

Other hypernyms of belch include breathe, emit.

belch (noun)	pass off (noun)
a reflex that expels gas noisily from the stomach through the mouth

belch (verb)	pass off (verb)
expel gas from the stomach	expel (gases or odors)
become active and spew forth lava and rocks	come to pass
	disappear gradually
	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