peel off vs slough

peel off is not a noun while slough is a noun.

Word	Noun	Adjective	Verb	Adverb
peel off	No	No	Yes	No
slough	Yes	No	Yes	No

As verbs, slough is a hypernym of peel off; that is, slough is a word with a broader meaning than peel off:

Other hypernyms of peel off include exuviate, molt, moult, shed.

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

peel off (verb)	slough (verb)
peel off in scales	cast off hair, skin, horn, or feathers
take off, as with some difficulty
peel off the outer layer of something
come off in flakes or thin small pieces
leave a formation