Related Clues:

• Attention-getting sound
• Have a bite
• Slangy hello
• 'Wait a minute!'
• ''Hey, bud!''
• Cousin of 'ahem'
• ''Hey, Mac!''
• Call for attention
• Head-turner
• Sibilant exclamation
• 'Stop right there!'
• Schweppes brand
• Call to share a secret?
• Verbal nudge
• Attention-getter, in the audience