Source : Webster's Revised Unabridged Dictionary (1913)

Acerbity \A*cerb"i*ty\, n. [F. acerbit['e], L. acerbitas, fr.
   acerbus. See {Acerb}.]
   1. Sourness of taste, with bitterness and astringency, like
      that of unripe fruit.

   2. Harshness, bitterness, or severity; as, acerbity of
      temper, of language, of pain. --Barrow.

Source : WordNet®

acerbity
     n 1: a sharp bitterness
     2: a sharp sour taste [syn: {tartness}]
     3: a sharp and bitter manner [syn: {bitterness}, {acrimony}, {jaundice}]