The Collaborative International Dictionary of English v.0.48:

Sofi \So"fi\, n.; pl. Sofis.
   Same as Sufi.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sufi \Su"fi\, n. [Ar. & Per. s?f[imac], wise, pious, devout.]
   One of a certain order of religious men in Persia. [Written
   also sofi.]
   [1913 Webster]