excretory vs excretion

excretory is not a noun while excretion is a noun.

Word	Noun	Adjective	Verb	Adverb
excretory	No	Yes	No	No
excretion	Yes	No	No	No

excretory (noun)	excretion (noun)
	the bodily process of discharging waste matter
	waste matter (as urine or sweat but especially feces) discharged from the body

excretory (adjective)	excretion (adjective)
of or relating to the process of excretion