Argus-eyed alert all ears all eyes attentive aux aguets aware cat-eyed clear-eyed clear-sighted custodial eagle-eyed eye-minded farseeing farsighted ferret-eyed guarded hawk-eyed keen keen-eyed lidless observant on guard on the lookout on the watch open-eyed prudent sharp sharp-sighted sleepless telescopic vigilant wary watchful with open eyes