belief vs perfidy

belief

noun
  • Mental acceptance of a claim as true. 

  • Religious faith. 

  • One's religious or moral convictions. 

  • The quality or state of believing. 

  • Faith or trust in the reality of something; often based upon one's own reasoning, trust in a claim, desire of actuality, and/or evidence considered. 

  • Something believed. 

perfidy

noun
  • A state or act of violating faith or allegiance; violation of a promise or vow, or of trust 

  • Specifically, in warfare, an illegitimate act of deception, such as using symbols like the Red Cross or white flag in a false claim of surrender to gain proximity to an enemy for purposes of attack. 

  • A state or act of deceit. 

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