acerbate vs irritate

acerbate

verb
  • To exasperate; to irritate. 

  • To make bitter or sour. 

adj
  • Embittered; having a sour disposition or nature. 

irritate

verb
  • To cause or induce displeasure or irritation. 

  • To induce pain in (all or part of a body or organism). 

  • To provoke impatience, anger, or displeasure in. 

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