Underhand

dishonest deceptive fraudulent tricky sly cunning crafty shady sneaky devious guileful underhanded duplicitous slippery treacherous crooked shifty insidious secret furtive stealthy dishonorable unscrupulous unethical unfair unjust two-faced double-crossing dirty-dealing wily concealed clandestine covert undercover surreptitious indirect two-timing secretive sneaking oblique under wraps hush-hush on the quiet sub-rosa on the QT