acuity ‘sharpness, acuteness’
Lexical development traced from the Tamil root:
E. acute, acuitye < O.F. acuite < Med.Lat. acuitatem ‘sharpness’ < Lat. acuere ‘to sharpen’ < acus ‘a needle’ < uhk < ak < Tamil akku
Other meanings: the capacity of a substance to cut; Medicine: the degree to which a disease or symptom is acute.