杞き憂ゆう

noun

needless fear; groundless apprehension; unfounded worry

A literary or formal expression for worrying about something that is extremely unlikely to happen. Often used in the phrase 杞憂に終わる (to prove to be a groundless fear).

• 彼かれの心しん配ぱいは結けっ局きょく杞き憂ゆうに終おわった。

  His worries turned out to be completely unfounded.

• そんなことを心しん配ぱいするなんて杞き憂ゆうだよ。

  Worrying about something like that is just needless fear.