Related Clues:

• ''Wait a minute!''
• ''You, over there!''
• With 29-Down, greeting for Mrs. Kowalski in 'A Streetcar Named Desire'
• Sibilant "Hey!"
• Soft "Hey!"
• "Psst!"
• Sound before 'Your fly's open'
• 'Over here'
• Start of a whispered comment, perhaps
• Subtle 'yo!'
• ''You there!''
• 'Hey . . . over here!'
• Sibilant signal
• Subtle alert
• Relative of ''ahem''