faecal matter vs muck

faecal matter and muck both are nouns.

Word	Noun	Adjective	Verb	Adverb
faecal matter	Yes	No	No	No
muck	Yes	No	Yes	No

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

Other hyponyms of faecal matter include dog do, dog shit, dog turd, doggy do, crap, dirt, poop, shit, shite, turd, droppings, dung, meconium, melaena, melena.

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

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