acerbate vs riot

acerbate

verb
  • To exasperate; to irritate. 

  • To make bitter or sour. 

adj
  • Embittered; having a sour disposition or nature. 

riot

verb
  • To annoy. 

  • To cause to riot; to throw into a tumult. 

  • To create or take part in a riot; to raise an uproar or sedition. 

noun
  • Wanton or unrestrained behavior or emotion. 

  • A humorous or entertaining event or person. 

  • A tumultuous disturbance of the public peace by a large group of people, often involving violence or damage to property. 

  • A wide and unconstrained variety. 

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