The Collaborative International Dictionary of English v.0.48:

Modernist \Mod"ern*ist\, n. [Cf. F. moderniste.]
   1. One who admires the moderns, or their ways and fashions.
      [1913 Webster]

   2. An advocate of the teaching of modern subjects, as modern
      languages, in preference to the ancient classics.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

modernist
    n 1: an artist who makes a deliberate break with previous styles