incentive vs satisfaction

incentive

noun
  • Something that motivates, rouses, or encourages. 

  • A bonus or reward, often monetary, to work harder. 

adj
  • Inciting; encouraging or moving; rousing to action; stimulating. 

  • Serving to kindle or set on fire. 

satisfaction

noun
  • A fulfilment of a need or desire. 

  • A reparation for an injury or loss. 

  • The pleasure obtained by such fulfillment. 

  • A vindication for a wrong suffered. 

  • The source of such gratification. 

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