the lack of ability to decide what to do, or the act of changing often between two opinions

The confusion about the project has been made worse by the vacillation and indecision. 摇摆不定和优柔寡断加剧了该项目的混乱。

There were some doubts and vacillations on this issue within the party. 党内对这个问题存在一些疑虑和动摇。