curdle vs lopper

curdle

verb
  • To form curds so that it no longer flows smoothly; to cause to form such curds. (usually said of milk) 

  • To cause a liquid to spoil and form clumps so that it no longer flows smoothly 

  • To clot or coagulate; to cause to congeal, such as through cold. (metaphorically of blood) 

lopper

verb
  • To turn sour and coagulate from too long standing, as milk. 

noun
  • A person who lops. 

  • A gardening tool used for lopping. 

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