Source : Webster's Revised Unabridged Dictionary (1913)

Socinian \So*cin"i*an\, n.
   One of the followers of Socinus; a believer in Socinianism.

Socinian \So*cin"i*an\, a.
   Of or pertaining to Socinus, or the Socinians.

Source : WordNet®

Socinian
     n : an adherent of the teachings of Socinus; a Christian who
         rejects the divinity of Christ and the Trinity and
         original sin; influenced the development of Unitarian
         theology