Source : Webster's Revised Unabridged Dictionary (1913)

Perspicacity \Per`spi*cac"i*ty\, n. [L. perspicacitas: cf. F.
   perspicacit['e]. See {Perspicacious}.]
   The state of being perspicacious; acuteness of sight or of
   intelligence; acute discernment. --Sir T. Browne.

Source : WordNet®

perspicacity
     n 1: intelligence manifested by being astute (as in business
          dealings) [syn: {shrewdness}, {astuteness}, {perspicaciousness}]
     2: the capacity to assess situations or circumstances shrewdly
        and to draw sound conclusions [syn: {judgment}, {judgement},
         {sound judgment}, {sound judgement}]