Related Clues:

• Low-key 'Hey!'
• ''Hey, this way!''
• ''Hey, you . . .''
• ''Hey, Buddy!''
• Discreet summons
• Attention-getting whisper
• Sound for attention
• "Yo!" in the library
• Tap-on-the-shoulder alternative
• It ain't exactly "Hey!"
• Sound from a test cheater, say
• Confidential warning
• 'Don't tell anyone, but...'
• Hushed ''Hey!''
• Classroom nudge