faecal matter vs dirt

faecal matter and dirt both are nouns.

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

As nouns, dirt is a hyponym of faecal matter; that is, dirt 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, poop, shit, shite, turd, droppings, dung, muck, meconium, melaena, melena.

faecal matter (noun)	dirt (noun)
solid excretory product evacuated from the bowels	disgraceful gossip about the private lives of other people
	anything regarded as making something unclean
	the part of the earth's surface consisting of humus and disintegrated rock
	obscene terms for feces

faecal matter (adjective)	dirt (adjective)
	(of roads) not leveled or drained; unsuitable for all year travel