abort vs knock off

abort

verb
  • To stop or fail at something in the preliminary stages. 

  • To cause a premature termination of (a fetus); to end a pregnancy before term. 

  • To abandon a mission at any point after the beginning of the mission and prior to its completion. 

  • To terminate a mission involving a missile or rocket; to destroy a missile or rocket prematurely. 

  • To end prematurely; to stop in the preliminary stages; to turn back. 

  • To miscarry; to bring forth (non-living) offspring prematurely. 

  • To become checked in normal development, so as either to remain rudimentary or shrink away wholly; to cease organic growth before maturation; to become sterile. 

  • To terminate a process prior to completion. 

  • To cause an organism to develop minimally; to cause rudimentary development to happen; to prevent maturation. 

noun
  • The function used to abort a process. 

  • An early termination of a mission, action, or procedure in relation to missiles or spacecraft; the craft making such a mission. 

  • An event in which a process is aborted. 

knock off

verb
  • To halt one's work or other activity. 

  • To rob. 

  • To defeat. 

  • To have sex with. 

  • To remove, as a discount or estimate. 

  • To make a copy of, as of a design. 

  • To assign (an item) to a bidder at an auction, indicated by knocking on the counter. 

  • To remove by hitting (something, someone) 

  • To kill. 

  • To accomplish hastily. 

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