fizzle out

US /ˈfɪz.əl aʊt/
UK /ˈfɪz.əl aʊt/
"fizzle out" picture
1.

立ち消えになる, しぼむ, 失敗に終わる

to end or fail in a weak or disappointing way after a promising start

:
The protest movement seemed to fizzle out after a few weeks.
抗議運動は数週間で立ち消えになったようだ。
Their initial enthusiasm for the project began to fizzle out.
彼らのプロジェクトに対する当初の熱意はしぼんでいった