Source : Webster's Revised Unabridged Dictionary (1913)

Perspicacious \Per`spi*ca"cious\, a. [L. perspicax, -acis, fr.
   perspicere to look through: cf. F. perspicace. See
   {Perspective}.]
   1. Having the power of seeing clearly; quick-sighted; sharp
      of sight.

   2. Fig.: Of acute discernment; keen. --
      {Per`spi*ca"cious*ly}, adv. -- {Per`spi*ca"cious*ness}, n.

Source : WordNet®

perspicacious
     adj 1: acutely insightful and wise; "much too perspicacious to be
            taken in by such a spurious argument"; "observant and
            thoughtful, he was given to asking sagacious
            questions"; "a source of valuable insights and sapient
            advice to educators" [syn: {sagacious}, {sapient}]
     2: mentally acute or penetratingly discerning; "too clear-eyed
        not to see what problems would follow"; "chaos could be
        prevented only by clear-sighted leadership"; "much too
        perspicacious to be taken in by so spurious an argument"
        [syn: {clear-eyed}, {clear-sighted}]