pourboire vs reward

pourboire

noun
  • A bribe. 

  • A tip (extra money given to e.g. a waiter in appreciation of service), especially in French contexts. 

reward

noun
  • A prize promised for a certain deed or catch 

  • Something of value given in return for an act. 

  • The result of an action, whether good or bad. 

verb
  • To give a reward to or for. 

  • To recompense. 

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