shit vs stool

shit and stool both are nouns.

Word	Noun	Adjective	Verb	Adverb
shit	Yes	No	Yes	No
stool	Yes	No	Yes	No

As nouns, stool is a hypernym of shit; that is, stool is a word with a broader meaning than shit:

Other hypernyms of shit include BM, dejection, faecal matter, faeces, fecal matter, feces, ordure.

As verbs, shit and stool are synonyms defined as:

Other synonyms of shit include ca-ca, crap, defecate, make, take a crap, take a shit.

shit (noun)	stool (noun)
something of little value	a simple seat without a back or arms
Obscene word for unacceptable behavior	a plumbing fixture for defecation and urination
insulting terms of address for people who are stupid or irritating or ridiculous	(forestry) the stump of a tree that has been felled or headed for the production of saplings
a coarse term for defecation	solid excretory product evacuated from the bowels
a small worthless amount
obscene terms for feces

shit (verb)	stool (verb)
have a bowel movement	have a bowel movement
give away information about somebody	grow shoots in the form of stools or tillers
	react to a decoy, of wildfowl
	lure with a stool, as of wild fowl