Liveliness, readiness, rapidity, or acuteness of feeling, perception, or apprehension. Physical acuteness, esp. of the senses.

Distinctness of vision, sound, expression, comprehension, etc.

a keen or sharp eye; cf. eagle-eyed, adj.

Keenness of sight. Obsolete.

The quality of being piercing or penetrating; keenness, sharpness.

As rendering of Latin acies. Keenness of eyesight. Obsolete.

Sharpness or keenness of perception; esp. clearness of vision (spec. for the shape or detail of objects).

Of power or faculty: Pertaining or relating to, concerned or connected with, sight or vision. visual acuity, sharpness of vision; spec. as measured…

visual acuity.

the sharpness of the eyes in discerning separation along the line of sight.