fall out vs come about

fall out and come about both are verbs.

Word	Noun	Adjective	Verb	Adverb
fall out	No	No	Yes	No
come about	No	No	Yes	No

As verbs, fall out and come about are synonyms defined as:

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

fall out (verb)	come about (verb)
come to pass	come to pass
have a breach in relations
drop out
leave (a barracks) in order to take a place in a military formation, or leave a military formation
come as a logical consequence; follow logically