fall out vs trigger

fall out is not a noun while trigger is a noun.

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

fall out (noun)	trigger (noun)
	an act that sets in motion some course of events
	lever that activates the firing mechanism of a gun
	a device that activates or releases or causes something to happen

fall out (verb)	trigger (verb)
come to pass	release or pull the trigger on
have a breach in relations	put in motion or move to act
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