buttress vs incentive

buttress

noun
  • Anything that supports or strengthens. 

  • A brick or stone structure built against another structure to support it. 

  • A buttress-root. 

  • Anything that serves to support something; a prop. 

  • A feature jutting prominently out from a mountain or rock. 

verb
  • To support something or someone by supplying evidence. 

  • To support something physically with, or as if with, a prop or buttress. 

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