To strike slightly or with some light instrument; especially, to strike with the nail of a finger first bent against the ball of the thumb, and let fly from that position with some force.To strike, nudge, or touch, as a horse or a person, in order to urge or press forward; incite; drive.To strike or tap with the nail of the finger.n. A jerk of a finger bent against the ball of the thumb, and then suddenly let fly; hence, a smart tap or stroke.n. Anything which tends to rouse, excite, or revive: as, that acted as a fillip to my spirits.