impossible or difficult to perceive by the mind or senses; "an imperceptible drop in temperature"; "an imperceptible nod"; "color is unperceivable to the touch"
marked 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"
having an import not apparent to the senses nor obvious to the intelligence; beyond ordinary understanding; "mysterious symbols"; "the mystical style of Blake"; "occult lore"; "the secret learning of the ancients"
(law) a conditional release from imprisonment that entitles the person to serve the remainder of the sentence outside the prison as long as the terms of release are complied with
a promise; "he gave his word"
release a criminal from detention and place him on parole; "The prisoner was paroled after serving 10 years in prison"