come about vs occur

come about and occur both are verbs.

Word	Noun	Adjective	Verb	Adverb
come about	No	No	Yes	No
occur	No	No	Yes	No

As verbs, come about and occur are synonyms defined as:

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

come about (verb)	occur (verb)
come to pass	come to pass
	come to one's mind; suggest itself
	to be found to exist