Related Clues:

• Secretive sound
• Hushed 'Hey!'
• "Hey!" in a library
• It may precede a tip
• Surreptitious signal
• 'Hey ... kid'
• ''C'mere!''
• "Ahem" alternative
• Discreet utterance
• Attention-grabbing sound
• "Hey," the quiet way
• Secret indicator
• Whispered ''Hey you!''
• "Wait a minute!"
• Alternative to being tapped