fillip

Short definition from Wiktionary

Noun

1. 1
   The action of holding the tip of a finger against the thumb and then releasing it with a snap; a flick.
2. 2
   A sharp strike or tap made using this action, or (by extension) by other means.
3. 3
   Something unimportant, a trifle; also, the brief time it takes to flick one's finger (see noun sense 1); a jiffy.
4. 4
   Something that excites or stimulates.

Verb

1. 1
   To strike, project, or propel with a fillip (that is, a finger released quickly after being pressed against the thumb); to flick.
2. 2
   To project quickly; to snap.
3. 3
   To strike or tap smartly.
4. 4
   To drive as if by a fillip (noun sense 1); to excite, stimulate, whet.
5. 5
   To make a fillip (noun sense 1) (with the fingers).