Main entry: vigilant, wakeful, open-eyed, argus-eyed
Definition: carefully observant or attentive; on the lookout for possible danger
Usage: a policy of open-eyed awareness; the vigilant eye of the town watch; there was a watchful dignity in the room; a watchful parent with a toddler in tow
Definition: marked by full consciousness or alertness
Usage: worked every moment of my waking hours
Definition: (of sleep) easily disturbed
Usage: in a light doze; a light sleeper; a restless wakeful night