gadfly vs incentive

gadfly

noun
  • A person or thing that irritates or instigates. 

  • Synonym of gadabout (“a person who restlessly moves from place to place, seeking amusement or the companionship of others”) 

  • Any dipterous (“two-winged”) insect or fly of the family Oestridae (commonly known as a botfly) or Tabanidae (horsefly), noted for irritating animals by buzzing about them, and biting them to suck their blood; a gadbee. 

  • A person who takes without giving back; a bloodsucker. 

  • A person who upsets the status quo by posing novel or upsetting questions, or attempts to stimulate innovation by being an irritant. 

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. 

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