incentive vs insistent

incentive

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

  • Serving to kindle or set on fire. 

noun
  • Something that motivates, rouses, or encourages. 

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

insistent

adj
  • Extorting attention or notice; coercively staring or prominent; vivid; intense. 

  • Urgent in dwelling upon anything; persistent in urging or maintaining. 

  • Standing on end: specifically said of the hind toe of a bird when its base is inserted so high on the shank that only its tip touches the ground: correlated with incumbent. 

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