cast off vs knock it off

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. 

knock it off

verb
  • To cease doing something, particulary annoying or unpleasant; to desist. 

intj
  • Cease doing something, particularly annoying or unpleasant; desist. 

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