ガタ落おち

noun, noun or participle which takes 'suru', intransitive verb

sharp drop; plunge; nosedive

Colloquial term for a sudden, steep decline in value, amount, quality, or reputation. Often used with する to mean 'to plummet'.

• 株かぶ価かがガタ落おちした。

  The stock price plummeted.

• 彼かれの評ひょう判ばんはガタ落おちだ。

  His reputation has taken a nosedive.