Related Clues:

• It'll shut you up
• ''Zip your lip!''
• ''No talking!''
• Theater injunction
• 'Quiet'
• Proctor's warning
• ''Quiet down!''
• Whisperer's comeuppance
• ''Be quiet!''
• "Use your inside voice!"
• Sound from a silencer
• Restraining order
• ''Stop talking!''
• Reaction to a big library volume?
• 'Not so loud!'