pretext vs prevarication

pretext

noun
  • A false, contrived, or assumed purpose or reason; a pretense. 

verb
  • To employ a pretext, which involves using a false or contrived purpose for soliciting the gain of something else. 

prevarication

noun
  • A false or deceitful seeming to undertake a thing for the purpose of defeating or destroying it. 

  • Evasion of the truth. 

  • A secret abuse in the exercise of a public office. 

  • The collusion of an informer with the defendant, for the purpose of making a sham prosecution. 

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