backroom vs internal affairs

backroom

adj
  • Characterized by secrecy or anonymity. 

  • Of, relating to, or happening in a backroom. 

noun
  • A room near the rear of a premises, especially one that is only accessible to a privileged few and can be used as an inconspicuous meeting place. 

internal affairs

noun
  • A division of a law enforcement agency investigating incidents and plausible suspicions of lawbreaking and professional misconduct attributed to officers on the force. 

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