hap vs fall out

hap is a noun but fall out is not a noun.

Word	Noun	Adjective	Verb	Adverb
hap	Yes	No	Yes	No
fall out	No	No	Yes	No

As verbs, hap and fall out are synonyms defined as:

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

hap (noun)	fall out (noun)
an accidental happening

hap (verb)	fall out (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