Related Clues:

• "It's a secret"
• Admonition in a library
• “Not another word!”
• Theater rebuke
• 'Inside voices!'
• “Quiet down!”
• "It's a secret!"
• ''Button it!''
• Reaction to someone tapping a microphone, maybe
• Librarian’s exhortation
• Library caution
• 'Don't say anything!'
• "Don't say anything!"
• Expressive silence
• Quiet hours allowing you and me to tuck in