Related Clues:

• Furtive utterance
• Sound made with a cupped hand
• "I'm waiting!"
• 'Don't you forget about me'
• “Hey, over here!”
• Tap-on-the shoulder alternative
• "Hey you, c'mere!"
• Sound that will get your attention
• "Don't tell anyone, but . . ."
• "Hey, you there!"
• "Attention please!"
• Secretive sound
• Hushed 'Hey!'
• "Hey!" in a library
• It may precede a tip