dejection vs excrement

dejection and excrement both are nouns.

Word	Noun	Adjective	Verb	Adverb
dejection	Yes	No	No	No
excrement	Yes	No	No	No

As nouns, excrement is a hypernym of dejection; that is, excrement is a word with a broader meaning than dejection:

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

Other hypernyms of dejection include body waste, excreta, excretion, excretory product.

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