cast a slur on vs defame

cast a slur on

defame

verb
  • To charge; to accuse (someone) of an offence. 

  • To harm or diminish the reputation of; to disparage. 

  • To disgrace; to bring into disrepute. 

How often have the words cast a slur on and defame occurred in a corpus of books? (source: Google Ngram Viewer )