acerbate vs mop

acerbate

verb
  • To make bitter or sour. 

  • To exasperate; to irritate. 

adj
  • Embittered; having a sour disposition or nature. 

mop

verb
  • To make a wry expression with the mouth. 

  • To shoplift. 

  • To rub, scrub, clean or wipe with a mop, or as if with a mop. 

noun
  • A wash with a mop; the act of mopping. 

  • An implement for washing floors or similar, made of a piece of cloth, or a collection of thrums, or coarse yarn, fastened to a handle. 

  • A dense head of hair. 

  • A made-up face; a grimace. 

  • A firearm particularly if it has a large magazine (compare broom, but still can be related to MP) 

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