ague vs knock out

ague

verb
  • To strike with an ague, or with a cold fit. 

noun
  • The cold fit or rigor of the intermittent fever 

  • A chill, or state of shaking, as with cold. 

  • An intermittent fever, attended by alternate cold and hot fits. 

knock out

verb
  • To strike or bump (someone or something) out. 

  • To fall asleep, especially suddenly. 

  • To lose the scent of hounds in fox-hunting. 

  • To eliminate from a contest or similar. 

  • To put to sleep. 

  • To complete, especially in haste; knock off. 

  • To render unconscious, as by a blow to the head. 

  • To exhaust. 

  • To cause a mechanism to become non-functional by damaging or destroying it. 

  • To communicate (a message) by knocking. 

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