尻しりすぼみ

noun

tapering off; weak ending; anticlimax

Describes something that starts strong but gradually loses momentum, becomes smaller, or ends weakly. Often used for stories, events, trends, or physical shapes that narrow toward the end.

• その映えい画がは前ぜん半はんは面おも白しろかったが、後こう半はんは尻しりすぼみだった。

  The movie was interesting in the first half, but the second half tapered off.

• 景けい気き回かい復ふくは尻しりすぼみに終おわった。

  The economic recovery ended in an anticlimax.