hap vs pass off

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

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

As verbs, hap and pass off are synonyms defined as:

Other synonyms of hap include come about, fall out, go on, happen, occur, pass, take place.

hap (noun)	pass off (noun)
an accidental happening

hap (verb)	pass off (verb)
come to pass	expel (gases or odors)
	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