The Collaborative International Dictionary of English v.0.48:

Raskolnik \Ras*kol"nik\ (r[a^]s*k[o^]l"n[i^]k), n.; pl.
   Raskolniki (r[a^]s*k[o^]l"n[i^]k*[=e]) or Raskolniks.
   [Russ. raskol'nik dissenter, fr. raskol dissent.]
   The name applied by the Russian government to any subject of
   the Greek faith who dissents from the established church. The
   Raskolniki embrace many sects, whose common characteristic is
   a clinging to antique traditions, habits, and customs. The
   schism originated in 1667 in an ecclesiastical dispute as to
   the correctness of the translation of the religious books.
   The dissenters, who have been continually persecuted, are
   believed to number about 20,000,000, although the Holy Synod
   officially puts the number at about 2,000,000. They are
   officially divided into three groups according to the degree
   of their variance from orthodox beliefs and observances, as
   follows: I. "Most obnoxious." the

   Judaizers; the

   Molokane, who refuse to recognize civil authority or to
      take oaths; the

   Dukhobortsy, or

   Dukhobors, who are communistic, marry without ceremony, and
      believe that Christ was human, but that his soul reappears
      at intervals in living men; the

   Khlysty, who countenance anthropolatory, are ascetics,
      practice continual self-flagellation, and reject marriage;
      the

   Skoptsy, who practice castration; and a section of the

   Bezpopovtsy, or priestless sect, which disbelieve in
      prayers for the Czar and in marriage. II. "Obnoxious:" the

   Bezpopovtsy, who pray for the Czar and recognize marriage.
      III. "Least obnoxious:" the

   Popovtsy, who dissent from the orthodox church in minor
      points only. [Written also rascolnik.]
      [Webster 1913 Suppl.]