The Collaborative International Dictionary of English v.0.48:

Ecclesiastic \Ec*cle`si*as"tic\ (?; 277), a. [L. ecclesiasticus,
   Gr. ?, fr. ? an assembly of citizens called out by the crier;
   also, the church, fr. ? called out, fr. ? to call out; 'ek
   out + ? to call. See Ex-, and Hale, v. t., Haul.]
   Of or pertaining to the church. See Ecclesiastical.
   "Ecclesiastic government." --Swift.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ecclesiastic \Ec*cle`si*as"tic\, n.
   A person in holy orders, or consecrated to the service of the
   church and the ministry of religion; a clergyman; a priest.
   [1913 Webster]

         From a humble ecclesiastic, he was subsequently
         preferred to the highest dignities of the church.
                                                  --Prescott.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ecclesiastic
    adj 1: of or associated with a church (especially a Christian
           Church); "ecclesiastic history" [syn: ecclesiastical,
           ecclesiastic]
    n 1: a clergyman or other person in religious orders [syn:
         cleric, churchman, divine, ecclesiastic]