1. made stronger, harder, or more resistant to damage
2. made emotionally stronger or more resilient through experience

1. past tense and past participle of toughen

Examples

• The toughened glass can withstand heavy impacts.
• Years of military service had toughened the veteran.
• The company toughened its security policies after the breach.
• She emerged from the ordeal toughened and more confident.
• The heat treatment toughened the metal considerably.
• His experiences had toughened him against criticism.
• The new regulations toughened penalties for violations.