gaffle vs knock off

gaffle

verb
  • To steal 

  • To arrest for criminal activity. 

  • To equip with a gaffle or similar weapon. 

  • To talk without a purpose, usually about inane or pointless topics; to babble. 

  • To grab or seize 

  • To get hold of, to find. 

  • To swindle or bully (someone) 

noun
  • A steel spur attached to a gamecock (sometimes used figuratively). 

  • A portable fork of iron or wood in which the heavy musket formerly in use was rested that it might be accurately aimed and fired. 

knock off

verb
  • To rob. 

  • To defeat. 

  • To halt one's work or other activity. 

  • 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 gaffle and knock off occurred in a corpus of books? (source: Google Ngram Viewer )