To project quickly; to snap.
To strike or tap smartly.
To drive as if by a fillip (noun sense 1); to excite, stimulate, whet.
To strike, project, or propel with a fillip (that is, a finger released quickly after being pressed against the thumb); to flick.
To make a fillip (noun sense 1) (with the fingers).
A sharp strike or tap made using this action, or (by extension) by other means.
Something unimportant, a trifle; also, the brief time it takes to flick one's finger (see noun sense 1); a jiffy.
Something that excites or stimulates.