pass water vs stool

pass water is not a noun while stool is a noun.

Word	Noun	Adjective	Verb	Adverb
pass water	No	No	Yes	No
stool	Yes	No	Yes	No

pass water (noun)	stool (noun)
	a simple seat without a back or arms
	a plumbing fixture for defecation and urination
	(forestry) the stump of a tree that has been felled or headed for the production of saplings
	solid excretory product evacuated from the bowels

pass water (verb)	stool (verb)
eliminate urine	have a bowel movement
	grow shoots in the form of stools or tillers
	react to a decoy, of wildfowl
	lure with a stool, as of wild fowl