defamation vs slander

defamation

noun
  • The act of injuring another person's reputation by any slanderous communication, written or oral; the wrong of maliciously injuring the good name of another. 

slander

noun
  • A false or unsupported, malicious statement (spoken, not written), especially one which is injurious to a person's reputation; the making of such a statement. 

  • A collection of humorous videos intended to poke fun at a certain group of people, such as a community or nation 

verb
  • To utter a slanderous statement about; baselessly speak ill of. 

  • To poke fun at a certain group of people 

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