Main entry: stealthy, surreptitious, sneak, sneaky, furtive
Definition: marked by quiet and caution and secrecy; taking pains to avoid being observed
Usage: a furtive manner; a sneak attack; stealthy footsteps; a surreptitious glance at his watch
Main entry: sneaky, underhand, underhanded
Definition: marked by deception
Usage: achieved success in business only by underhand methods