1. past tense of nosedive; to plunge or dive steeply downward, especially of an aircraft
Usage: often used in aviation contexts
2. to decline sharply or suddenly, as in value, performance, or condition
Usage: figurative use

Examples

• The stock market nosedove after the announcement.
• The airplane nosedove through the clouds during the emergency descent.
• His grades nosedove when he stopped studying.
• The company's profits nosedove in the fourth quarter.
• The diver nosedove into the pool from the high platform.
• Consumer confidence nosedove following the economic crisis.