| acuity | (n) sharpness of vision; the visual ability to resolve fine detail (usually measured by a Snellen chart), Syn. sharp-sightedness, visual acuity |
| alertness | (n) lively attentiveness, Syn. sharp-sightedness, on the qui vive |
| argus-eyed | (adj) having very keen vision, Syn. hawk-eyed, keen-sighted, lynx-eyed, sharp-sighted, sharp-eyed, quick-sighted, Example: quick-sighted as a cat |
| quick-sighted | (adj) keenly perceptive or alert; - Leonard Bacon, Syn. sharp-sighted, sharp-eyed, Example: quick-sighted into the faults of the time |
