body waste vs dejection

body waste and dejection both are nouns.

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

As nouns, dejection is a hyponym of body waste; that is, dejection is a word with a more specific, narrower meaning than body waste:

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

body waste (noun)	dejection (noun)
waste matter (as urine or sweat but especially feces) discharged from the body	a state of melancholy depression
	solid excretory product evacuated from the bowels