backstair vs sad

backstair

adj
  • clandestine, secret or furtive 

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

sad

adj
  • Unfashionable; socially inadequate or undesirable. 

  • Soggy (to refer to pastries). 

  • Causing sorrow; lamentable. 

  • Of colours: dark, deep; later, sombre, dull. 

  • Appearing sorrowful. 

  • Feeling sorrow; sorrowful, mournful. 

  • Poor in quality, bad; shameful, deplorable; later, regrettable, poor. 

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