The Collaborative International Dictionary of English v.0.48:

expressionism \expressionism\ n.
   1. an art movement early in the 20th century; the artist's
      subjective expression of inner experiences was emphasized.
      [WordNet 1.5]

   2. a genre of German painting that tried to show the
      subjective responses to scenes rather than the scenes
      themselves.
      [WordNet 1.5] expressionist

WordNet (r) 3.0 (2006):

expressionism
    n 1: an art movement early in the 20th century; the artist's
         subjective expression of inner experiences was emphasized;
         an inner feeling was expressed through a distorted
         rendition of reality

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "expressionism":
   abstractionism, coloring, deformation, distortion, exaggeration,
   false coloring, falsification, garbling, hyperbole, inaccuracy,
   injustice, litotes, miscoloring, misdrawing, mispainting,
   misquotation, misreport, misrepresentation, misstatement,
   misteaching, nonrealism, overdrawing, overstatement, perversion,
   slanting, twisting, understatement