buy vs buy off

buy

verb
  • To bribe. 

  • To make a purchase or purchases, to treat (for a drink, meal or gift) 

  • To make a bluff, usually a large one. 

  • To be equivalent to in value. 

  • To obtain (something) in exchange for money or goods. 

  • To obtain, especially by some sacrifice. 

  • to accept as true; to believe 

noun
  • Something which is bought; a purchase. 

buy off

verb
  • To pay off, convince to refrain etc. by corrupt payment or other service. 

  • To gain release for (a person) from military service by payment of money. 

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