Definition of "acuity" []

• Acuteness of vision or perception; keenness. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "AGENT ORANGE, annoyed: Your visual acuity is uncanny."
• "Terry Pratchett, who has early-onset Alzheimer's (and whose mental acuity is still fine) has written a stirring editorial on the need to legalize suicide in the UK."
• "She just turned 90, and her mental acuity is better than most people half her age."