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