fillip

fillip \FIL-uhp\, noun:

1. A snap of the finger forced suddenly from the thumb; a smart blow.
2. Something serving to rouse or excite; a stimulus.
3. A trivial addition; an embellishment.
4. To strike with the nail of the finger, first placed against the ball of the thumb, and forced from that position with a sudden spring; to snap with the finger.
5. To snap; to project quickly.
6. To urge on; to provide a stimulus, by or as if by a fillip.

If any one in Mirgorod gives him a neckerchief or underclothes, he returns thanks; if any one gives him a fillip on the nose--he returns thanks then also.
-- Nikolai Gogol, "The Tale of How Ivan Ivanovich Quarrelled with Ivan Nikiforovich"

You fillip me o' the head.
-- Shakespeare, Troilus and Cressida

Her raspberry cream tart is given an added fillip with bourbon and nutmeg.
-- Marian Burros, "Cooking", New York Times, June 3, 1984

The utopian and romantic -- and in the end completely unrealistic -- idea that the building should serve as a mooring post for airships led to the creation of a tower on the tower, giving a final fillip to the design.
-- Nathan Glazer, "Miracle on 34th Street", New York Times, December 3, 1995

Fillip is probably of imitative origin.