the.com/fizzle
The sound of ambition deflating in slow, audible disappointment.
means To start with promise and then weaken, sputter, and end in failure or anticlimax.
from From the 1530s fysel, meaning to break wind quietly — a soft hiss that history politely repurposed for failed fireworks and flopped plans.
Original senseA discreet, silent fart
OnomatopoeiaThe word imitates a dying hiss
Fizzle outCommon since the 1840s American slang