acu·​i·​ty ə-ˈkyü-ə-tē How to pronounce acuity (audio)
plural acuities
: keenness of perception
hearing acuity
mental acuity

Did you know?

Do you have acuity or sensitivity?

Acuity is nearly synonymous with at least one sense of sensitivity, yet, as is so often the case with closely-related words, there are subtle differences worth observing before you substitute one of these words for the other. Acuity does refer to a form of sensitivity, but it is most often applied to the perceptual senses (as in “visual acuity” or “auditory acuity”). It is also frequently used in reference to the intellect (as in “mental acuity”). Sensitivity has a broader range of meanings than acuity does, including “the capacity of being easily hurt.” It may be used of inanimate objects such as radios (“the sensitivity of the instruments was carefully calibrated”), a context in which acuity is unusual.

Examples of acuity in a Sentence

a worrisome deterioration in the acuity of his hearing over the years
Recent Examples on the Web Massa also drew attention to his opponent's often aggressive rhetoric and openly questioned his mental acuity. Bradford Betz, Fox News, 20 Nov. 2023 Interviews with voters polled showed that for many, the negative feelings about Mr. Biden stemmed from doubts about his mental acuity. Camille Baker, New York Times, 7 Nov. 2023 To make matters worse, an infection had spread from the incision site, causing rapid deterioration of Bob’s mental acuity. Globe Staff,, 7 Sep. 2023 In 2023, the quest for enhanced cognitive performance has become increasingly prominent, with individuals from various walks of life seeking ways to optimize their mental acuity and concentration. Amber Smith, Discover Magazine, 11 July 2023 Some described heart-wrenching scenes as Willis grappled with his loss of mental acuity and an inability to remember his dialogue, The Times reported previously. Nardine Saad, Los Angeles Times, 12 Oct. 2023 Questions about Biden’s age and mental acuity, justified or not, have emerged as some of the biggest vulnerabilities for the president’s reelection campaign, polls suggest. Maeve Reston and Marisa Iati, Anchorage Daily News, 19 Sep. 2023 This product extends beyond athletes, providing assistance in cellular energy production and mental acuity, enabling individuals to excel in all aspects of life at their highest potential. Amber Smith, Discover Magazine, 22 July 2023 Vanessa Bell Calloway’s Idella, a cook who works for Ol’ Cap’n and might in other contexts be framed as a Mammy figure, here has a freedom fighter’s acuity. Jesse Green, New York Times, 27 Sep. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'acuity.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Middle English acuite "sharpness, acridity," borrowed from Middle French acuité, borrowed from Medieval Latin acuitāt-, acuitās, from Latin acu-, stem of acuere "to sharpen" + -itāt-, -itās -ity — more at acute

First Known Use

circa 1549, in the meaning defined above

Time Traveler
The first known use of acuity was circa 1549

Dictionary Entries Near acuity

Cite this Entry

“Acuity.” Dictionary, Merriam-Webster, Accessed 6 Dec. 2023.

Kids Definition


acu·​ity ə-ˈkyü-ət-ē How to pronounce acuity (audio)
: sharpness of perception

Medical Definition


acu·​ity ə-ˈkyü-ət-ē How to pronounce acuity (audio)
plural acuities
: keenness of sense perception
acuity of hearing
see visual acuity

More from Merriam-Webster on acuity

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!