feces vs muck

feces and muck both are nouns.

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

As nouns, muck is a hyponym of feces; that is, muck is a word with a more specific, narrower meaning than feces:

feces (noun)	muck (noun)
solid excretory product evacuated from the bowels	any thick, viscous matter
	fecal matter of animals

feces (verb)	muck (verb)
	remove muck, clear away muck, as in a mine
	soil with mud, muck, or mire
	spread manure, as for fertilization