cast off vs throw away

cast off

verb
  • To discard or reject something. 

  • To let go (a cable or rope securing a vessel to a buoy, wharf, etc.) so that the vessel may make way. 

  • To finish the last row of knitted stitches and remove them securely from the needle. 

  • To estimate the amount of space required by the type used for the given copy. 

throw away

verb
  • To discard (trash, garbage, or the like), to toss out, to put in the trash, to dispose of. 

  • To intentionally throw an incomplete pass. 

  • To waste, to squander. 

  • To give lightly, in an offhand manner. 

How often have the words cast off and throw away occurred in a corpus of books? (source: Google Ngram Viewer )