Source : Webster's Revised Unabridged Dictionary (1913)

Falsity \Fal"si*ty\, n.;pl. {Falsities}. [L. falsitas: cf. F.
   fausset['e], OF. also, falsit['e]. See {False}, a.]
   1. The quality of being false; coutrariety or want of
      conformity to truth.

            Probability does not make any alteration, either in
            the truth or falsity of things.       --South.

   2. That which is false; falsehood; a lie; a false assertion.

            Men often swallow falsities for truths. --Sir T.
                                                  Brown.

   Syn: Falsehood; lie; deceit.

   Usage: {Falsity}, {Falsehood}, {Lie}. Falsity denotes the
          state or quality of being false. A falsehood is a
          false declaration designedly made. A lie is a gross,
          unblushing falsehood. The falsity of a person's
          assertion may be proved by the evidence of others and
          thus the charge of falsehood be fastened upon him.

Source : WordNet®

falsity
     n 1: the state of being false or untrue; "argument could not
          determine its truth or falsity" [syn: {falseness}] [ant:
           {truth}]
     2: a false statement [syn: {falsehood}, {untruth}, {false
        statement}] [ant: {truth}]