concealment vs facade

concealment

noun
  • The condition of being hidden or concealed. 

  • The practice of keeping secrets. 

  • protection from observation or surveillance. 

facade

noun
  • A deceptive or insincere outward appearance. 

  • An object serving as a simplified interface to a larger body of code, as in the facade pattern. 

  • The face or front (most visible side) of any other thing, such as an organ. 

  • The face of a building, especially the front view or elevation. 

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