The Collaborative International Dictionary of English v.0.48:

Syncretic \Syn*cret"ic\, a.
   Uniting and blending together different systems, as of
   philosophy, morals, or religion. --Smart.
   [1913 Webster]

WordNet (r) 3.0 (2006):

syncretic
    adj 1: relating to a historical tendency for a language to
           reduce its use of inflections; "modern English is a
           syncretic language" [syn: syncretic, syncretical,
           syncretistic, syncretistical]
    2: of or characterized by syncretism [syn: syncretic,
       syncretical, syncretistic, syncretistical]