Related Clues:

• Start of a whispered comment, perhaps
• Subtle 'yo!'
• ''You there!''
• 'Hey . . . over here!'
• Familiar greeting
• Sibilant signal
• Subtle alert
• Relative of ''ahem''
• Soft "Yo! Over here!"
• Furtive ''Yo!''
• Note passer's signal
• Head-turning sound
• Clandestine call
• 'Hey, neighbor!'
• ''Wassup!''