The Collaborative International Dictionary of English v.0.48:

Prevaricator \Pre*var"i*ca`tor\, n. [L. praevaricator: cf. F.
   pr['e]varicateur.]
   1. One who prevaricates.
      [1913 Webster]

   2. (Roman Law) A sham dealer; one who colludes with a
      defendant in a sham prosecution.
      [1913 Webster]

   3. One who betrays or abuses a trust. --Prynne.
      [1913 Webster]

WordNet (r) 3.0 (2006):

prevaricator
    n 1: a person who has lied or who lies repeatedly [syn: liar,
         prevaricator] [ant: square shooter, straight arrow,
         straight shooter]

The Devil's Dictionary (1881-1906):

PREVARICATOR, n.  A liar in the caterpillar estate.