Main entry: 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
Antonyms: unvigilant, unwatchful, unalert
Definition: not alert to what is potentially dangerous
Antonyms: lidded
Definition: having or covered with a lid or lids; often used in combination
Main entry: awake, alert, alive
Definition: mentally perceptive and responsive
Usage: an alert mind; alert to the problems; alive to what is going on; awake to the dangers of her situation; was now awake to the reality of his predicament
Antonyms: incognizant, unaware
Definition: (often followed by `of') not aware
Main entry: rattling, alert, spanking, snappy, zippy, brisk, merry, lively
Definition: quick and energetic
Usage: a brisk walk in the park; a lively gait; a merry chase; traveling at a rattling rate; a snappy pace; a spanking breeze
Antonyms: unenrgetic, lethargic
Definition: deficient in alertness or activity