muck vs muck up

muck is a noun but muck up is not a noun.

Word	Noun	Adjective	Verb	Adverb
muck	Yes	No	Yes	No
muck up	No	No	Yes	No

As verbs, muck and muck up are synonyms defined as:

Other synonyms of muck include mire, mud.

muck (noun)	muck up (noun)
any thick, viscous matter
fecal matter of animals

muck (verb)	muck up (verb)
remove muck, clear away muck, as in a mine	soil with mud, muck, or mire
soil with mud, muck, or mire	make a mess of, destroy or ruin
spread manure, as for fertilization