The Collaborative International Dictionary of English v.0.48:

Falsehood \False"hood\, n. [False + -hood]
   1. Want of truth or accuracy; an untrue assertion or
      representation; error; misrepresentation; falsity.
      [1913 Webster]

            Though it be a lie in the clock, it is but a
            falsehood in the hand of the dial when pointing at a
            wrong hour, if rightly following the direction of
            the wheel which moveth it.            --Fuller.
      [1913 Webster]

   2. A deliberate intentional assertion of what is known to be
      untrue; a departure from moral integrity; a lie.
      [1913 Webster]

   3. Treachery; deceit; perfidy; unfaithfulness.
      [1913 Webster]

            Betrayed by falsehood of his guard.   --Shak.
      [1913 Webster]

   4. A counterfeit; a false appearance; an imposture.
      [1913 Webster]

            For his molten image is falsehood.    --Jer. x. 14.
      [1913 Webster]

            No falsehood can endure
            Touch of celestial temper.            --Milton.

   Syn: Falsity; lie; untruth; fiction; fabrication. See
        Falsity.
        [1913 Webster]

WordNet (r) 3.0 (2006):

falsehood
    n 1: a false statement [syn: falsehood, falsity, untruth]
         [ant: true statement, truth]
    2: the act of rendering something false as by fraudulent changes
       (of documents or measures etc.) or counterfeiting [syn:
       falsification, falsehood]