backstairs

• POS: Adjective, Noun Plural
• HYPHEN: back=stairs

CIDE DICTIONARY

backstairs, n. 

 Stairs in the back part of a house, as distinguished from the front stairs; a second staircase at the rear of a building; hence, a private or indirect way.  [1913 Webster]

backstairs, 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]

OXFORD DICTIONARY

backstairs, n.pl.
1 stairs at the back or side of a building.
2 (also backstair) (attrib.) denoting underhand or clandestine activity.

THESAURUS

backstairs

back-door, clandestine, covert, feline, furtive, hidlings, hole-and-corner, hugger-mugger, privy, quiet, shifty, skulking, slinking, slinky, sly, sneaking, sneaky, stealthy, surreptitious, under-the-counter, under-the-table, undercover, underground, underhand, underhanded, unobtrusive