Related Clues:

• Sound from a test cheater, say
• Confidential warning
• Like good watchmen
• 'Don't tell anyone, but...'
• Hushed ''Hey!''
• Classroom nudge
• Fully awake
• Sibilant call
• Bright-eyed
• Subtle signal
• Verbal elbow?
• Subtle "Over here!"
• ''What's that I hear?''
• Start of a library volume discussion?
• "Yo, over here!"