knock back vs poleaxe

knock back

verb
  • To stun; to surprise. 

  • To drink an alcoholic beverage swiftly or often. 

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

  • To reject; to refuse. 

poleaxe

verb
  • To astonish; to shock or surprise utterly. 

  • To fell someone with, or as if with, a poleaxe. 

  • To stymie, thwart, cripple, paralyze. 

noun
  • An ax having both a blade and a hammer face; used to slaughter cattle. 

  • A long-handled battle axe, being a combination of ax, hammer and pike. 

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