Related Clues:

• Fully attentive
• Flag or flare
• Like good watchmen
• Fully awake
• Bright-eyed
• Give a heads-up
• Nod or wink
• Type of post-caffeine state
• Percipient
• ''Heads up!'' e.g.
• Sound the alarm
• Far from drowsy
• Not asleep on the job
• Storm posting, e.g.
• Like a sentry