attrit vs knock down

attrit

verb
  • To be reduced in quantity through attrition. 

  • To lose, or to kill, troops by attrition due to sustained firepower. 

  • To engage in attrition; to quit or drop out. 

  • To wear down through attrition, especially mechanical attrition. 

noun
  • One who voluntarily or involuntarily leaves a company; a termed employee. 

knock down

verb
  • To reduce the price of. 

  • To drink fast. 

  • To disassemble for shipment. 

  • To hit or knock (something or someone), intentionally or accidentally, so that it falls. 

  • To demolish. 

  • To approve a drinking toast by banging glasses on the table. 

  • At an auction, to declare (something) sold with a blow from the gavel. 

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