acerbate vs rile

acerbate

verb
  • To make bitter or sour. 

  • To exasperate; to irritate. 

adj
  • Embittered; having a sour disposition or nature. 

rile

verb
  • To make angry. 

  • To stir or move from a state of calm or order. 

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