Adjective: Argus-eyed
- Carefully observant or attentive; on the lookout for possible danger
"a policy of Argus-eyed awareness";
- open-eyed, vigilant, wakeful, watchful
- Having keen eyesight; quick to notice visual details
"The Argus-eyed ranger spotted the bird a mile away";
- hawk-eyed, keen-sighted, lynx-eyed, quick-sighted, sharp-eyed, sharp-sighted, eagle-eyed