happen vs come about

happen and come about both are verbs.

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

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

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

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

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

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

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

happen (verb)	come about (verb)
come to pass	come to pass
come into being; become reality
happen, occur, or be the case in the course of events or by chance
come upon, as if by accident; meet with
chance to be or do something, without intention or causation