1. to make or become tough, strong, or resilient
Usage: third person singular present tense of ‘toughen’

Examples

• The coach toughens his players with intense training.
• Cold weather toughens the skin.
• Experience toughens a person’s character.
• The metal toughens when heated and cooled repeatedly.
• Military service toughens young recruits.
• Hard work toughens your resolve.
• The leather toughens with age and use.