Related Clues:

• With ears pricked
• Not nodding
• Red flag, e.g.
• Prepared for action
• Well-known McCartney
• Caffeinated?
• 'A Street-car Named Desire' role
• Trouble indicator
• Not dozing
• Not nodding
• 'Look out below!,' e.g.
• 'A Streetcar Named Desire' woman
• Awake and aware
• Having pricked ears
• Keen-eyed