incentive vs obsession

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. 

obsession

noun
  • An activity or entity that inspires a compulsive and potentially unhealthy fixation, or the fixation thereby inspired. 

  • An idea that engenders a compulsive or irrational preoccupation, or the preoccupation thereby engendered. 

  • The quality of being obsessed. 

  • Influence or control by evil spirits without possession. 

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