acerbate vs bemoan

acerbate

verb
  • To make bitter or sour. 

  • To exasperate; to irritate. 

adj
  • Embittered; having a sour disposition or nature. 

bemoan

verb
  • To moan or complain about (something). 

  • To be dismayed or worried about (someone), particularly because of their situation or what has happened to them. 

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