Related Clues:

• 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!''
• Alternative to being tapped
• 'Hey, you'
• 'Hey ... you'
• "Hey, buddy!"
• Sibilant sound to attract attention furtively