acerbate vs yammer

acerbate

verb
  • To make bitter or sour. 

  • To exasperate; to irritate. 

adj
  • Embittered; having a sour disposition or nature. 

yammer

verb
  • To complain peevishly. 

  • To repeat on and on, usually loudly or in complaint. 

  • To make an outcry; to clamor. 

  • To talk loudly and persistently. 

noun
  • A loud noise. 

  • One who yammers. 

  • The act or noise of yammering. 

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