1. failed completely or collapsed
2. (of a ship) filled with water and sank
Usage: nautical
3. (of a horse) became lame or fell
Usage: equestrian

Examples

• The startup foundered after losing its major investor.
• Their marriage foundered due to constant disagreements.
• The ship foundered in the storm and all hands were lost.
• The expedition foundered when they ran out of supplies.
• His political career foundered after the scandal broke.
• The horse foundered on the rocky terrain.
• The peace talks foundered over territorial disputes.