acerbate vs grate

acerbate

verb
  • To exasperate; to irritate. 

  • To make bitter or sour. 

adj
  • Embittered; having a sour disposition or nature. 

grate

verb
  • To get on one's nerves; to irritate, annoy. 

  • To annoy. 

  • To shred (things, usually foodstuffs), by rubbing across a grater. 

  • To make an unpleasant rasping sound, often as the result of rubbing against something. 

  • To furnish with grates; to protect with a grating or crossbars. 

noun
  • A horizontal metal grill through which water, ash, or small objects can fall, while larger objects cannot. 

  • A frame or bed, or kind of basket, of iron bars, for holding fuel while burning. 

  • A grapper, a metal ring on a lance behind the grip. 

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