suck up vs mop up

suck up is not a noun while mop up is a noun.

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

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

Other hyponyms of suck up include mop, wipe up, blot, sponge up.

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

suck up (verb)	mop up (verb)
try to gain favor by cringing or flattering	finish a task completely
take in, also metaphorically	defeat thoroughly
ingratiate oneself to; often with insincere behavior	to wash or wipe with or as if with a mop