abettor vs incentive

abettor

noun
  • One that abets an offender; one that incites; instigates; encourages. 

  • A supporter or advocate. 

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 abettor and incentive occurred in a corpus of books? (source: Google Ngram Viewer )