noun

To fail or become ineffective.

Example

1. John had high hopes of becoming a pilot, but he washed out of flight school after failing his final exams.
2. The new restaurant in town had a lot of hype, but it quickly washed out after receiving a string of bad reviews.
3. The construction company's plan to build a new bridge over the river washed out when they discovered that the riverbed was too unstable to support the bridge's foundation.