NOUN (3)

1. a Roman Catholic priest who acts for another higher-ranking clergyman;

2. (Episcopal Church) a clergyman in charge of a chapel;

3. (Church of England) a clergyman appointed to act as priest of a parish;

The Collaborative International Dictionary of English v.0.48:

Vicar \Vic"ar\ (v[i^]k"[~e]r), n. [OE. vicar, viker, vicair, F.
   vicaire, fr. L. vicarius. See Vicarious.]
   1. One deputed or authorized to perform the functions of
      another; a substitute in office; a deputy. [R.]
      [1913 Webster]

   2. (Eng. Eccl. Law) The incumbent of an appropriated
      benefice.
      [1913 Webster]

   Note: The distinction between a parson [or rector] and vicar
         is this: The parson has, for the most part, the whole
         right to the ecclesiastical dues in his parish; but a
         vicar has generally an appropriator over him, entitled
         to the best part of the profits, to whom he is in fact
         perpetual curate with a standing salary. --Burrill.
         [1913 Webster]

   Apostolic vicar, or Vicar apostolic. (R. C. Ch.)
      (a) A bishop to whom the Roman pontiff delegates a portion
          of his jurisdiction.
      (b) Any ecclesiastic acting under a papal brief,
          commissioned to exercise episcopal authority.
      (c) A titular bishop in a country where there is no
          episcopal see, or where the succession has been
          interrupted.

   Vicar forane. [Cf. LL. foraneus situated outside of the
      episcopal city, rural. See Vicar, and Foreign.] (R. C.
      Ch.) A dignitary or parish priest appointed by a bishop to
      exercise a limited jurisdiction in a particular town or
      district of a diocese. --Addis & Arnold.

   Vicar-general.
      (a) (Ch. of Eng.) The deputy of the Archbishop of
          Canterbury or York, in whose court the bishops of the
          province are confirmed. --Encyc. Brit.
      (b) (R. C. Ch.) An assistant to a bishop in the discharge
          of his official functions.

   Vicar of Jesus Christ (R. C. Ch.), the pope as representing
      Christ on earth.
      [1913 Webster]
      [1913 Webster]

WordNet (r) 3.0 (2006):

vicar
    n 1: a Roman Catholic priest who acts for another higher-ranking
         clergyman
    2: (Episcopal Church) a clergyman in charge of a chapel
    3: (Church of England) a clergyman appointed to act as priest of
       a parish

Moby Thesaurus II by Grady Ward, 1.0:

112 Moby Thesaurus words for "vicar":
   Grand Penitentiary, Holy Father, abuna, advocate, agent, alter ego,
   alternate, alternative, amicus curiae, analogy, antipope,
   archbishop, archdeacon, archpriest, attorney, backup, backup man,
   bishop, bishop coadjutor, canon, cardinal, cardinal bishop,
   cardinal deacon, cardinal priest, champion, change, changeling,
   chaplain, coadjutor, comparison, copy, counterfeit, curate, dean,
   deputy, diocesan, double, dummy, ecclesiarch, equal, equivalent,
   ersatz, exarch, exchange, executive officer, exponent, fake,
   figurehead, fill-in, ghost, ghostwriter, hierarch, high priest,
   imitation, lieutenant, locum, locum tenens, makeshift, metaphor,
   metonymy, metropolitan, next best thing, papa, paranymph,
   patriarch, penitentiary, personnel, phony, pinch hitter, pleader,
   pontiff, pope, prebendary, prelate, primate, procurator, proxy,
   rector, relief, replacement, representative, reserves, ringer,
   rural dean, second in command, second string, secondary, sign,
   spares, stand-in, sub, subdean, substituent, substitute,
   substitution, succedaneum, suffragan, superseder, supplanter,
   surrogate, symbol, synecdoche, third string, token, understudy,
   utility man, utility player, vicar general, vice, vice-president,
   vice-regent, vicegerent