backstairs

/B AE1 K S T EH0 R Z/
noun
  1. 1

    A staircase at the rear of a building or one normally only used by servants and tradesmen.

  2. 2

    An indirect or furtive means of access or intercourse.

adjective
  1. 1

    Secret or furtive.

  2. 2

    Scandalous.

Synonyms

Source: https://en.wiktionary.org/wiki/backstairs