Related Clues:

• It might scream after being tripped
• Eyeopener?
• Warning signal
• Put on notice
• Vigilantly attentive
• Not out of it
• Firebox feature
• *Siren ... danger ... perked up
• Trepidation
• Warning
• Warning device
• Security system part
• Attention-getting sound
• Perceptive
• Sound the tocsin