acerbity (n.)
1570s, from Middle French acerbité, from Latin acerbitatem (nominative acerbitas) "harshness, sharpness, bitterness," from acerbus "bitter to taste, sharp, sour, tart" (related to acer "sharp;" compare Latin superbus "haughty," from super "above"), from Proto-Italic *akro-po- "sharp," from PIE *ak- "sharp" (see acrid). Earliest use in English is figurative, of "sharp and bitter" persons. Of tastes, from 1610s.