backstair vs resistance

backstair

noun
  • The backstairs (stairs at the rear of a building). 

adj
  • clandestine, secret or furtive 

resistance

noun
  • The act of resisting, or the capacity to resist. 

  • An underground organisation engaged in a struggle for liberation from forceful occupation; a resistance movement. 

  • A force that tends to oppose motion. 

  • electrical resistance. 

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