fizzle out：
Fail, end weakly, especially after a hopeful beginning. For example, The enthusiasm for reform has fizzled out in this state. The word fizzle dates from the early 1500s and meant “to break wind without making noise.” Later it was applied to hissing noises, such as those made by wet fireworks, and then to any endeavor that ends in disappointment. [Colloquial; mid-1800s]
