Related Clues:

• See 21-Down
• Became frayed
• Eroded away
• Like wine
• Matured, as wine
• Ripened
• Fatigued (with ''down'')
• Like mellower wines
• Seasoned
• Like some cheeses
• Got threadbare
• Made cheddar better
• Matured, like wine
• Like balsamic vinegar
• Like good swiss