pass off vs bubble

pass off is not a noun while bubble is a noun.

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

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

Other hyponyms of pass off include belch, burp, eruct, force out, emanate, exhale, give forth, radiate.

pass off (noun)	bubble (noun)
	a dome-shaped covering made of transparent glass or plastic
	an impracticable and illusory idea
	a speculative scheme that depends on unstable factors that the planner cannot control
	a hollow globule of gas (e.g., air or carbon dioxide)

pass off (verb)	bubble (verb)
expel (gases or odors)	expel gas from the stomach
come to pass	form, produce, or emit bubbles
disappear gradually	cause to form bubbles
disregard	rise in bubbles or as if in bubbles
cause to be circulated and accepted in a false character or identity	flow in an irregular current with a bubbling noise
be accepted as something or somebody in a false character or identity