The Collaborative International Dictionary of English v.0.48:

Communicant \Com*mu"ni*cant\ (k[o^]m*m[=u]"n[i^]*kant), n. [L.
   communicans, p. pr.]
   1. One who partakes of, or is entitled to partake of, the
      sacrament of the Lord's supper; a church member.
      [1913 Webster]

            A never-failing monthly communicant.  --Atterbury.
      [1913 Webster]

   2. One who communicates. --Foxe.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Communicant \Com*mu"ni*cant\ (k[o^]m*m[=u]"n[i^]*kant), a.
   Communicating. [R.] --Coleridge.
   [1913 Webster]

WordNet (r) 3.0 (2006):

communicant
    n 1: a person entitled to receive Communion

Moby Thesaurus II by Grady Ward, 1.0:

83 Moby Thesaurus words for "communicant":
   Christian, God-fearing man, accepter, adorer, adviser, announcer,
   annunciator, authority, beadsman, believer, brother, catechumen,
   celebrant, channel, chapelgoer, church member, churchgoer,
   churchite, churchman, churchwoman, communicator, congregation,
   convert, daily communicant, devotee, devotionalist, disciple,
   enlightener, evangelist, expert witness, fanatic, follower,
   good Christian, gossipmonger, grapevine, idolater, informant,
   information center, information medium, informer, interviewee,
   laic, lay brother, lay sister, layman, laywoman, monitor,
   mouthpiece, neophyte, newsmonger, notifier, parishioner,
   petitioner, pietist, prayer, press, proselyte,
   public relations officer, publisher, radio, receiver, religionist,
   reporter, revivalist, saint, secular, sister, source, spokesman,
   suppliant, supplicant, supplicator, television, teller, theist,
   tipster, tout, truster, venerator, votary, witness, worshiper,
   zealot