carefully observant or attentive; on the lookout for possible danger
"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"
Watchful, especially for danger or disorder; alert; wary
"The security guard remained vigilant as he scanned the parking lot for any suspicious activity after dark."