Related Clues:

• Hushed 'Hey!'
• "Hey!" in a library
• It may precede a tip
• Surreptitious signal
• Indicate "yes" silently
• Lash flash?
• 'Hey ... kid'
• ''C'mere!''
• Sleep precursor
• "Ahem" alternative
• Discreet utterance
• Signal agreement
• Attention-grabbing sound
• "Hey," the quiet way
• Secret indicator