sop up vs mop

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

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

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

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

sop up (noun)	mop (noun)
	cleaning implement consisting of absorbent material fastened to a handle; for cleaning floors

sop up (verb)	mop (verb)
take up as if with a sponge	make a sad face and thrust out one's lower lip
take in, also metaphorically	to wash or wipe with or as if with a mop