acerbate vs curd

acerbate

verb
  • To exasperate; to irritate. 

  • To make bitter or sour. 

adj
  • Embittered; having a sour disposition or nature. 

curd

verb
  • To cause to coagulate or thicken; to cause to congeal; to curdle. 

  • To form curd; to curdle. 

noun
  • The edible flower head of certain brassicaceous plants. 

  • The coagulated part of any liquid. 

  • The part of milk that coagulates when it sours or is treated with enzymes; used to make cottage cheese, dahi, etc. 

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