backstair vs way-out

backstair

adj

  • clandestine, secret or furtive 

noun

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

way-out

adj

  • unusual, unconventional or strange 

  • out of the mainstream of society 

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