fratricide vs slaughtering

fratricide

noun
  • The intentional or unintentional killing of a comrade in arms. 

  • A person who commits fratricide. 

  • The killing of one's brother (or sister). 

  • The undesirable situation where the separate missiles from a MIRV interfere with each other as they explode. 

slaughtering

noun
  • An act of slaughter; a killing. 

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