cover-up vs pretext

cover-up

noun
  • An attempt to conceal or disguise something, especially a wrongdoing or a mistake. 

  • An item of clothing to be worn over a swimsuit while not in the water. 

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. 

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