thin; not dense or gross; rare; as, subtile air; subtile vapor; a subtile medium.-delicately constituted or constructed; nice; fine; delicate; tenuous; finely woven.-acute; piercing; searching.-characterized by nicety of discrimination; discerning; delicate; refined; subtle.-sly; artful; cunning; crafty; subtle; as, a subtile person; a subtile adversary; a subtile scheme.