backstair

back=stair

WORDNET DICTIONARY

backstair(s = adj.all) backstairs, furtive - secret and sly or sordid; "backstairs gossip"; "his low backstairs cunning"; "backstairs intimacies"; "furtive behavior"

backstair, a.

Private; indirect; secret; conducted with secrecy; intriguing; -- as if finding access by the back stairs; as, backstairs gossip. [1913 Webster]

"A backstairs influence." [1913 Webster]

"Female caprice and backstair influence." [1913 Webster]