calumny vs muckrake

calumny

verb
  • To make false accusations or levy false charges against a person with the intent to tarnish that person's reputation or standing; to calumniate. 

noun
  • Falsifications or misrepresentations intended to disparage or discredit another. 

  • A false accusation or charge brought to tarnish another's reputation or standing. 

muckrake

verb
  • To search for and expose corruption or scandal, especially as a form of investigative journalism. 

noun
  • A rake for scraping up dung. 

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