knock back vs spurn

knock back

verb
  • To reject; to refuse. 

  • To drink an alcoholic beverage swiftly or often. 

  • To stun; to surprise. 

  • To press or knead (dough) so as to remove air bubbles. 

spurn

verb
  • To reject disdainfully; contemn; scorn. 

  • To waste; fail to make the most of (an opportunity) 

  • To reject something by pushing it away with the foot. 

noun
  • An act of spurning; a scornful rejection. 

  • A kick; a blow with the foot. 

  • A body of coal left to sustain an overhanging mass. 

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