Related Clues:

• 21-year-old, by most accounts
• Stage of growth
• R-rated, say
• Full-grown
• Kind of education
• 18-and-over
• Grown up
• Grown-up
• Full-price payer
• Voter, e.g.
• One old enough to know better
• Former minor
• Full price payer
• Chaperone, usually
• Film category