break up vs crunch

break up is not a noun while crunch is a noun.

Word	Noun	Adjective	Verb	Adverb
break up	No	No	Yes	No
crunch	Yes	No	Yes	No

As verbs, crunch is a hyponym of break up; that is, crunch is a word with a more specific, narrower meaning than break up:

Other hyponyms of break up include atomise, atomize, bray, comminute, grind, mash, pound, sunder, sliver, splinter, rag, crumb, brecciate, crush, grate, grind.

break up (noun)	crunch (noun)
	the act of crushing
	the sound of something crunching
	a critical situation that arises because of a shortage (as a shortage of time or money or resources)

break up (verb)	crunch (verb)
laugh unrestrainedly	reduce to small pieces or particles by pounding or abrading
break or cause to break into pieces	make a crushing noise
come to an end	crush with the teeth, making a grinding sound
separate (substances) into constituent elements or parts	press or grind with a crushing noise
cause to go into a solution
cause to separate
close at the end of a session
bring the association of to an end or cause to break up
make a break in
set or keep apart
break violently or noisily; smash
attack with or as if with a pickaxe of ice or rocky ground, for example
release ice
destroy the completeness of a set of related items
take apart into its constituent pieces
suffer a nervous breakdown
disband
to cause to separate and go in different directions
discontinue an association or relation; go different ways