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]

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "ecclesiastic":
   DD, Doctor of Divinity, Holy Joe, abbe, chaplain, churchman,
   clergyman, cleric, clerical, clerk, curate, cure, divine,
   man of God, military chaplain, minister, padre, parson, pastor,
   preacher, rector, reverend, servant of God, shepherd, sky pilot,
   supply clergy, supply minister, the Reverend, the very Reverend,
   tonsured cleric



Bouvier's Law Dictionary, Revised 6th Ed (1856):

ECCLESIASTIC. A clergyman; one destined to the divine ministry, as, a
bishop, a priest, a deacon. Dom. Lois Civ. liv. prel. t. 2, s. 2, n. 14.