Nosedive (verb)

To suddenly decline or drop sharply.

Origin:

Nose + dive.

Examples:

1. The stock market took a nosedive after the announcement.
2. The company's profits took a nosedive last quarter.
3. The team's performance took a nosedive after the coach was fired.
4. The popularity of the app took a nosedive after the update.
5. The airplane went into a nosedive before it could recover.