The Collaborative International Dictionary of English v.0.48:

Falsification \Fal`si*fi*ca"tion\, n. [Cf. F. falsification.]
   1. The act of falsifying, or making false; a counterfeiting;
      the giving to a thing an appearance of something which it
      is not.
      [1913 Webster]

            To counterfeit the living image of king in his
            person exceedeth all falsifications.  --Bacon.
      [1913 Webster]

   2. Willful misstatement or misrepresentation.
      [1913 Webster]

            Extreme necessity . . . forced him upon this bold
            and violent falsification of the doctrine of the
            alliance.                             --Bp.
                                                  Warburton.
      [1913 Webster]

   3. (Equity) The showing an item of charge in an account to be
      wrong. --Story.
      [1913 Webster]

WordNet (r) 3.0 (2006):

falsification
    n 1: any evidence that helps to establish the falsity of
         something [syn: disproof, falsification, refutation]
    2: a willful perversion of facts [syn: falsification,
       misrepresentation]
    3: the act of rendering something false as by fraudulent changes
       (of documents or measures etc.) or counterfeiting [syn:
       falsification, falsehood]
    4: the act of determining that something is false [syn:
       falsification, falsifying, disproof, refutation,
       refutal]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "falsification":
   abstractionism, coloring, confabulation, deformation, distortion,
   equivocation, exaggeration, expressionism, false coloring,
   false swearing, falsifying, garbling, hyperbole, inaccuracy,
   injustice, litotes, miscoloring, misconstruction, misdrawing,
   mispainting, misquotation, misreport, misrepresentation,
   misstatement, misteaching, nonrealism, overdrawing, overstatement,
   perjury, perversion, prevarication, slanting, straining, twisting,
   understatement