fall out vs spark

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

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

fall out (noun)	spark (noun)
	merriment expressed by a brightness or gleam or animation of countenance
	a momentary flash of light
	a small fragment of a burning substance thrown out by burning material or by friction
	electrical conduction through a gas in an applied electric field
	a small but noticeable trace of some quality that might become stronger

fall out (verb)	spark (verb)
come to pass	put in motion or move to act
have a breach in relations	emit or produce sparks
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