throw away vs cast off

throw away and cast off both are verbs.

Word	Noun	Adjective	Verb	Adverb
throw away	No	No	Yes	No
cast off	No	No	Yes	No

As verbs, throw away and cast off are synonyms defined as:

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

throw away (verb)	cast off (verb)
to remove	to remove
throw or cast away	make the last row of stitches when knitting