excretion vs feces

excretion and feces both are nouns.

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

As nouns, feces is a hyponym of excretion; that is, feces is a word with a more specific, narrower meaning than excretion:

excretion: waste matter (as urine or sweat but especially feces) discharged from the body
feces: solid excretory product evacuated from the bowels

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