cast off vs go back

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. 

go back

verb
  • To go back on. 

  • To return to a place or state after having been there at a previous time. 

  • To have known each other for a certain length of time. 

  • To extend into past time. 

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