The Collaborative International Dictionary of English v.0.48:

Disciple \Dis*ci"ple\, v. t. [imp. & p. p. Discipled; p. pr. &
   vb. n. Discipling.]
   1. To teach; to train. [Obs.]
      [1913 Webster]

            That better were in virtues discipled. --Spenser.
      [1913 Webster]

   2. To punish; to discipline. [Obs.] --B. Jonson.
      [1913 Webster]

   3. To make disciples of; to convert to doctrines or
      principles. [R.]
      [1913 Webster]

            Sending missionaries to disciple all nations. --E.
                                                  D. Griffin.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Disciple \Dis*ci"ple\, n. [OE. disciple, deciple, OF. disciple,
   fr. L. discipulus, fr. discere to learn (akin to docere to
   teach; see Docile) + prob. a root meaning to turn or drive,
   as in L. pellere to drive (see Pulse).]
   One who receives instruction from another; a scholar; a
   learner; especially, a follower who has learned to believe in
   the truth of the doctrine of his teacher; an adherent in
   doctrine; as, the disciples of Plato; the disciples of our
   Savior.
   [1913 Webster]

   The disciples, or The twelve disciples, the twelve
      selected companions of Jesus; -- also called the
      apostles.

   Disciples of Christ. See Christian, n., 3, and
      Campbellite.

   Syn: Learner; scholar; pupil; follower; adherent.
        [1913 Webster]

WordNet (r) 3.0 (2006):

disciple
    n 1: someone who believes and helps to spread the doctrine of
         another [syn: disciple, adherent]

Moby Thesaurus II by Grady Ward, 1.0:

105 Moby Thesaurus words for "disciple":
   Ambrose of Milan, Athanasius, Barnabas, Basil, Christian,
   Clement of Alexandria, Clement of Rome, Cyprian of Carthage,
   Cyril of Jerusalem, God-fearing man, Gregory of Nyssa, Hermas,
   Ignatius, Irenaeus, Jerome, John, John Chrysostom, Justin Martyr,
   Lactantius Firmianus, Luke, Mark, Origen, Papias, Paul, Peter,
   Polycarp, Tertullian, accepter, adherent, admirer, aficionado,
   ante-Nicene Fathers, apostle, appendage, apprentice, attendant,
   believer, buff, catechumen, cavaliere servente, churchgoer,
   churchite, churchman, cohort, communicant, convert, courtier,
   creature, daily communicant, dangler, dependent, devotee,
   devotionalist, dummy, enthusiast, evangelist, fan, fanatic,
   figurehead, flunky, follower, following, gillie, good Christian,
   goon, hanger-on, henchman, homme de cour, jackal, lackey, learner,
   man, minion, myrmidon, neophyte, parasite, partisan, pietist,
   proselyte, public, pupil, puppet, pursuer, pursuivant, receiver,
   religionist, saint, satellite, scholar, sectary, shadow, stooge,
   student, successor, supporter, sycophant, tagtail, tail, theist,
   thug, trainbearer, truster, votary, ward heeler, zealot



Easton's 1897 Bible Dictionary:

Disciple
   a scholar, sometimes applied to the followers of John the
   Baptist (Matt. 9:14), and of the Pharisees (22:16), but
   principally to the followers of Christ. A disciple of Christ is
   one who (1) believes his doctrine, (2) rests on his sacrifice,
   (3) imbibes his spirit, and (4) imitates his example (Matt.
   10:24; Luke 14:26, 27, 33; John 6:69).