Possible Clues:

• Grown-up people
• Grown-ups, mature people
• Voters and drinkers, e.g.
• Accomplishes mundane tasks, facetiously
• A lust for round about five hundred of those no longer 9 across
• They're not kids anymore
• Non-minor league?
• Co-signers for minors
• Mature persons a police officer has arrested in the last month
• Characters not seen in "Peanuts"