Source : Webster's Revised Unabridged Dictionary (1913)

Untruth \Un*truth"\, n.
   1. The quality of being untrue; contrariety to truth; want of
      veracity; also, treachery; faithlessness; disloyalty.
      --Chaucer.

   2. That which is untrue; a false assertion; a falsehood; a
      lie; also, an act of treachery or disloyalty. --Shak.

   Syn: Lie; falsehood. See {Lie}.

Source : WordNet®

untruth
     n : a false statement [syn: {falsehood}, {falsity}, {false
         statement}] [ant: {truth}]