The Collaborative International Dictionary of English v.0.48:

Unconformist \Un`con*form"ist\, n.
   A nonconformist. [Obs.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

unconformist
    adj 1: not conforming to some norm or socially approved pattern
           of behavior or thought; "their rabidly nonconformist
           deportment has made them legendary"; "the old stubborn
           nonconformist spirit of the early settlers" [syn:
           nonconformist, unconformist] [ant: conformist]