Source : Webster's Revised Unabridged Dictionary (1913)

Perspicuous \Per*spic"u*ous\, a. [L. perspicuus, from perspicere
   to look through. See {Perspective}.]
   1. Capable of being through; transparent; translucent; not
      opaque. [Obs.] --Peacham.

   2. Clear to the understanding; capable of being clearly
      understood; clear in thought or in expression; not obscure
      or ambiguous; as, a perspicuous writer; perspicuous
      statements. ``The purpose is perspicuous.'' --Shak. --
      {Per*spic"u*ous*ly}, adv. -- {Per*spic"u*ous*ness}, n.

Source : WordNet®

perspicuousness
     n : clarity as a consequence of being perspicuous [syn: {perspicuity},
          {plainness}]