形容词

1. 警惕的;警觉的；警戒的
Someone who is vigilant gives careful attention to a particular problem or situation and concentrates on noticing any danger or trouble that there might be.

1. carefully observant or attentive
on the lookout for possible danger

e.g. 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

Synonym: argus-eyedopen-eyedwakeful