acuity Play nounSharpness or keenness of thought, vision, or hearing. SYNONYMS acuityacutenessastutenessclarityclevernessdiscernmentdiscriminationincisivenessinsightintelligencekeennessperceptionperceptivenesspercipienceperspicacityperspicuityprofundityquick-wittednesssagacitysensitivitysharp-wittednesssharpnessshrewdnesssmartnesssubtletythoughtfulnesstrenchancy