excrement vs wormcast

excrement and wormcast both are nouns.

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

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

excrement: waste matter (as urine or sweat but especially feces) discharged from the body
wormcast: cylindrical mass of earth voided by a burrowing earthworm or lugworm

excrement (noun)	wormcast (noun)
waste matter (as urine or sweat but especially feces) discharged from the body	fossil trail of a worm
	cylindrical mass of earth voided by a burrowing earthworm or lugworm