Source : Webster's Revised Unabridged Dictionary (1913)

Unfrock \Un*frock"\, v. t. [1st pref. un- + frock.]
   To deprive or divest or a frock; specifically, to deprive of
   priestly character or privilege; as, to unfrock a priest.

Source : WordNet®

unfrock
     v : divest of the frock; of church officials [syn: {defrock}]