defamation vs slam piece

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. 

slam piece

noun
  • A journalistic or other treatment which portrays its subject in a highly unfavorable manner. 

  • A sexual partner to whom one has no particular emotional attachment. 

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