Source : Webster's Revised Unabridged Dictionary (1913)

Sufism \Su"fism\, n.
   A refined mysticism among certain classes of Mohammedans,
   particularly in Persia, who hold to a kind of pantheism and
   practice extreme asceticism in their lives. [Written also
   {sofism}.]

Source : WordNet®

Sufism
     n : Islamic mysticism