While today fizzle has such noble meanings as "to fail or end feebly especially after a promising start," the word has origins of a baser sort. Fizzle is thought to be an alteration of the Middle English fist ("flatus"), which in addition to providing us with the verb for breaking wind quietly, was also munificent enough to serve as the basis for a now-obsolete noun meaning "a silent fart" (feist).
Had the Rump but once fizled 'twas the strongest side,
But a Fart has so routed his Troop in their pride,
Though infallible Butler was his guide,
That they are both blown down the wind.
— Anon., A Display of the Headpiece and Codpiece Valour of the Most Renowned Colonel Robert Jermy, 1660