reward vs sweetener

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. 

sweetener

noun
  • A shill bidder at an auction. 

  • Something added to food to sweeten its taste, especially an artificial substitute for sugar. 

  • Something given or added to added to a deal to sweeten another's attitude, especially a bribe or kickback. 

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