1. causing death
2. causing ruin or failure; disastrous

Examples

• The car accident proved fatal for two passengers.
• A fatal dose of poison was found in his system.
• The company made a fatal error in their marketing strategy.
• Her fatal flaw was trusting people too easily.
• The disease is often fatal if left untreated.
• That decision was fatal to his political career.
• The fatal shooting occurred late at night.