come up vs hap

come up is not a noun while hap is a noun.

Word	Noun	Adjective	Verb	Adverb
come up	No	No	Yes	No
hap	Yes	No	Yes	No

As verbs, hap is a hypernym of come up; that is, hap is a word with a broader meaning than come up:

Other hypernyms of come up include come about, fall out, go on, happen, occur, pass, pass off, take place.

come up (noun)	hap (noun)
	an accidental happening

come up (verb)	hap (verb)
result or issue	come to pass
start running, functioning, or operating
gather or bring together
gather (money or other resources) together over time
bring forth, usually something desirable
come up, of celestial bodies
come to the surface
move toward, travel toward something or somebody or approach something or somebody
move upward
get something or somebody for a specific purpose
originate or come into being
be mentioned