Synset

carefully observant or attentive; on the lookout for possible danger
<adj.all>   freq. cnt.: 5 freq. cnt.: 5

argus-eyed

open-eyed

vigilant

wakeful

sample sentences

"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"