Related Clues:

• Bright-eyed
• Start the day
• Give a heads-up
• Tossing and turning
• Type of post-caffeine state
• Percipient
• React to an alarm
• ''Heads up!'' e.g.
• Sound the alarm
• Far from drowsy
• Not asleep on the job
• No longer dozing
• Storm posting, e.g.
• Warning notice
• Like a sentry