mop up vs rack up

mop up is a noun but rack up is not a noun.

Word	Noun	Adjective	Verb	Adverb
mop up	Yes	No	Yes	No
rack up	No	No	Yes	No

As verbs, mop up and rack up are synonyms defined as:

Other synonyms of mop up include pip, whip, worst.

mop up (noun)	rack up (noun)
a concluding action

mop up (verb)	rack up (verb)
finish a task completely	supply a rack with feed for (horses or other animals)
defeat thoroughly	defeat thoroughly
to wash or wipe with or as if with a mop	gain points in a game
	place in a rack