moult vs cast off

moult is a noun but cast off is not a noun.

Word	Noun	Adjective	Verb	Adverb
moult	Yes	No	Yes	No
cast off	No	No	Yes	No

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

Other hypernyms of moult include cast, drop, shake off, shed, throw, throw away, throw off.

moult (noun)	cast off (noun)
periodic shedding of the cuticle in arthropods or the outer skin in reptiles

moult (verb)	cast off (verb)
cast off hair, skin, horn, or feathers	to remove
	make the last row of stitches when knitting