Open English Wordnet
Adjectives
(s)furtive, sneak, sneaky, stealthy, surreptitiousmarked by quiet and caution and secrecy; taking pains to avoid being observed“a furtive manner”,
“a sneak attack”,
“stealthy footsteps”,
“a surreptitious glance at his watch” (s)backstair, backstairs, furtivesecret and sly or sordid“backstairs gossip”,
“his low backstairs cunning” (A.L.Guerard),
“backstairs intimacies”,
“furtive behavior”