slough vs natural covering

slough and natural covering both are nouns.

Word	Noun	Adjective	Verb	Adverb
slough	Yes	No	Yes	No
natural covering	Yes	No	No	No

As nouns, natural covering is a hypernym of slough; that is, natural covering is a word with a broader meaning than slough:

slough: any outer covering that can be shed or cast off (such as the cast-off skin of a snake)
natural covering: a natural object that covers or envelops

Other hypernyms of slough include cover, covering.

slough (noun)	natural covering (noun)
any outer covering that can be shed or cast off (such as the cast-off skin of a snake)	a natural object that covers or envelops
necrotic tissue; a mortified or gangrenous part or mass
a stagnant swamp (especially as part of a bayou)
a hollow filled with mud

slough (verb)	natural covering (verb)
cast off hair, skin, horn, or feathers