faeces vs dog shit

faeces and dog shit both are nouns.

Word	Noun	Adjective	Verb	Adverb
faeces	Yes	No	No	No
dog shit	Yes	No	No	No

As nouns, dog shit is a hyponym of faeces; that is, dog shit is a word with a more specific, narrower meaning than faeces:

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

faeces (noun)	dog shit (noun)
solid excretory product evacuated from the bowels	fecal droppings from a dog