mop up vs clear up

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

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

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

Other synonyms of mop up include finish off, finish up, get through, polish off, wrap up.

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

mop up (verb)	clear up (verb)
finish a task completely	free (the throat) by making a rasping sound
defeat thoroughly	finish a task completely
to wash or wipe with or as if with a mop	make free from confusion or ambiguity; make clear
	make clear and (more) comprehensible
	become clear