stool vs take a leak

stool is a noun but take a leak is not a noun.

Word	Noun	Adjective	Verb	Adverb
stool	Yes	No	Yes	No
take a leak	No	No	Yes	No

stool (noun)	take a leak (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

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