The Collaborative International Dictionary of English v.0.48:

conformist \conformist\ adj.
   1. marked by conformity or convention; not corresponding to
      current customs or rules or styles; as, underneath the
      radical image teenagers are surprisingly conformist.
      Opposite of nonconformist.
      [WordNet 1.5]

   2. same as conforming.

   Note: [Narrower terms: orthodox (vs. unorthodox)]

   Syn: conforming.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Conformist \Con*form"ist\, n.
   One who conforms or complies; esp., one who conforms to the
   Church of England, or to the Established Church, as
   distinguished from a dissenter or nonconformist.
   [1913 Webster]

         A cheeful conformist to your judgment.   --Jer.Taylor.
   [1913 Webster]

WordNet (r) 3.0 (2006):

conformist
    adj 1: marked by convention and conformity to customs or rules
           or styles; "underneath the radical image teenagers are
           surprisingly conformist" [ant: nonconformist,
           unconformist]
    2: adhering to established customs or doctrines (especially in
       religion) [syn: conforming, conformist]
    n 1: someone who conforms to established standards of conduct
         (especially in religious matters) [ant: nonconformist,
         recusant]