blacken vs calumniate

blacken

verb
  • To defame or sully. 

  • To make dirty. 

  • To cook (meat or fish) by coating with pepper, etc., and quickly searing in a hot pan. 

  • To become black. 

  • To cause to be or become black. 

calumniate

verb
  • To make hurtful untrue comments about. 

  • To levy a false charge against, especially of a vague offense, with the intent to damage someone's reputation or standing. 

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