acerbate vs get under one's goat

acerbate

verb
  • To exasperate; to irritate. 

  • To make bitter or sour. 

adj
  • Embittered; having a sour disposition or nature. 

get under one's goat

verb
  • To irritate or annoy someone; to bother. 

How often have the words acerbate and get under one's goat occurred in a corpus of books? (source: Google Ngram Viewer )