rid vs throw off

rid

verb
  • To free (something) from a hindrance or annoyance. 

adj
  • Released from an obligation, problem, etc. (usually followed by of). 

throw off

verb
  • To expel, reject, or renounce. 

  • To give forth in an unpremeditated manner. 

  • Of a horse, to eject its rider. 

  • To introduce errors or inaccuracies; to skew. 

  • To confuse; especially, to lose a pursuer. 

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