当あて外はずれ

noun, noun which may take the genitive case particle 'no'

disappointment; letdown

Refers to a situation or outcome that falls short of expectations; often used when hopes or predictions are not met.

• 試し験けんの結けっ果かは当あて外はずれだった。

  The exam results were a disappointment.

• 当あて外はずれな天てん気きでピクニックは中ちゅう止しになった。

  The picnic was canceled due to the unexpectedly disappointing weather.