1. (noun) sharpness of vision; the visual ability to resolve fine detail (usually measured by a Snellen chart)

• acuity
• visual acuity

2. (noun) lively attentiveness

• alertness
• on the qui vive

1. (noun) sharpness of vision; the visual ability to resolve fine detail (usually measured by a Snellen chart)

• 20/20
• twenty-twenty
• oxyopia

1. (noun) sharpness of vision; the visual ability to resolve fine detail (usually measured by a Snellen chart)

• sight
• vision
• visual modality
• visual sense

2. (noun) lively attentiveness

• attentiveness

1. (noun) sharpness of vision; the visual ability to resolve fine detail (usually measured by a Snellen chart)

• argus-eyed
• hawk-eyed
• keen-sighted
• lynx-eyed
• quick-sighted
• sharp-eyed
• sharp-sighted

2. (noun) lively attentiveness

• alert
• watchful
• quick-sighted
• sharp-eyed
• sharp-sighted