shake off vs slough

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

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

As verbs, slough is a hyponym of shake off; that is, slough is a word with a more specific, narrower meaning than shake off:

Other hyponyms of shake off include exuviate, molt, moult, shed, abscise, exfoliate, autotomise, autotomize.

shake 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

shake off (verb)	slough (verb)
to remove	cast off hair, skin, horn, or feathers
get rid of