acerbate vs take umbrage

acerbate

verb
  • To make bitter or sour. 

  • To exasperate; to irritate. 

adj
  • Embittered; having a sour disposition or nature. 

take umbrage

verb
  • To become angry and resentful. 

  • To take offense. 

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