Synonyms: 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
Similar words: alert, watchful
Definition: engaged in or accustomed to close observation
Usage: caught by a couple of alert cops; alert enough to spot the opportunity when it came; constantly alert and vigilant, like a sentinel on duty
Definition: marked by full consciousness or alertness
Usage: worked every moment of my waking hours
Similar words: awake
Definition: not in a state of sleep; completely conscious
Usage: lay awake thinking about his new job; still not fully awake
Definition: (of sleep) easily disturbed
Usage: in a light doze; a light sleeper; a restless wakeful night
Similar words: shallow
Definition: not deep or strong; not affecting one deeply
Usage: shallow breathing; a night of shallow fretful sleep; in a shallow trance