The Collaborative International Dictionary of English v.0.48:

Schismatic \Schis*mat"ic\ (s[i^]z*m[a^]t"[i^]k; so nearly all
   orthoepists), a. [L. schismaticus, Gr. ?: cf. F.
   schismatique.]
   Of or pertaining to schism; implying schism; partaking of the
   nature of schism; tending to schism; as, schismatic opinions
   or proposals.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Schismatic \Schis*mat"ic\ (?; 277), n.
   One who creates or takes part in schism; one who separates
   from an established church or religious communion on account
   of a difference of opinion. "They were popularly classed
   together as canting schismatics." --Macaulay.
   [1913 Webster]

   Syn: Heretic; partisan. See Heretic.
        [1913 Webster]

WordNet (r) 3.0 (2006):

schismatic
    adj 1: of or relating to or involved in or characteristic of
           schism; "schismatic sects" [syn: schismatic,
           schismatical]