gunk vs sapropel

gunk and sapropel both are nouns.

Word	Noun	Adjective	Verb	Adverb
gunk	Yes	No	No	No
sapropel	Yes	No	No	No

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

gunk: any thick, viscous matter
sapropel: sludge (rich in organic matter) that accumulates at the bottom of lakes or oceans

gunk (noun)	sapropel (noun)
any thick, viscous matter	sludge (rich in organic matter) that accumulates at the bottom of lakes or oceans