Related Clues:

• Full of NoDoz
• Not dozing
• Fully attentive
• Like good watchmen
• Fully awake
• Bright-eyed
• Cautious (of)
• Give a heads-up
• Type of post-caffeine state
• Percipient
• Careful
• ''Heads up!'' e.g.
• Sound the alarm
• Far from drowsy
• Not asleep on the job