body waste vs excretion

body waste and excretion both are nouns.

Word	Noun	Adjective	Verb	Adverb
body waste	Yes	No	No	No
excretion	Yes	No	No	No

As nouns, body waste and excretion are synonyms defined as:

body waste and excretion: waste matter (as urine or sweat but especially feces) discharged from the body

Other synonyms of body waste include excrement, excreta, excretory product.

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