NOUN (1)

1. a religious person who believes Jesus is the Christ and who is a member of a Christian denomination;


ADJECTIVE (2)

1. relating to or characteristic of Christianity;
- Example: "Christian rites"

2. following the teachings or manifesting the qualities or spirit of Jesus Christ;

The Collaborative International Dictionary of English v.0.48:

Christian \Chris"tian\, a.
   1. Pertaining to Christ or his religion; as, Christian
      people.
      [1913 Webster]

   3. Pertaining to the church; ecclesiastical; as, a Christian
      court. --Blackstone.
      [1913 Webster]

   4. Characteristic of Christian people; civilized; kind;
      kindly; gentle; beneficent.
      [1913 Webster]

            The graceful tact; the Christian art. --Tennyson.
      [1913 Webster]

   Christian Commission. See under Commission.

   Christian court. Same as Ecclesiastical court.

   Christian Endeavor, Young People's Society of. In various
      Protestant churches, a society of young people organized
      in each individual church to do Christian work; also, the
      whole body of such organizations, which are united in a
      corporation called the United Society of Christian
      Endeavor, organized in 1885. The parent society was
      founded in 1881 at Portland, Maine, by Rev. Francis E.
      Clark, a Congregational minister. [Webster 1913 Suppl.]

   Christian era, the present era, commencing with the birth
      of Christ. It is supposed that owing to an error of a monk
      (Dionysius Exiguus, d. about 556) employed to calculate
      the era, its commencement was fixed three or four years
      too late, so that 1890 should be 1893 or 1894.

   Christian name, the name given in baptism, as distinct from
      the family name, or surname.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Christian \Chris"tian\, n. [L. christianus, Gr. ?; cf. AS.
   cristen. See Christ.]
   [1913 Webster]
   1. One who believes, or professes or is assumed to believe,
      in Jesus Christ, and the truth as taught by Him;
      especially, one whose inward and outward life is conformed
      to the doctrines of Christ.
      [1913 Webster]

            The disciples were called Christians first in
            Antioch.                              --Acts xi. 26.
      [1913 Webster]

   2. One born in a Christian country or of Christian parents,
      and who has not definitely becomes an adherent of an
      opposing system.
      [1913 Webster]

   3. (Eccl.)
      (a) One of a Christian denomination which rejects human
          creeds as bases of fellowship, and sectarian names.
          They are congregational in church government, and
          baptize by immersion. They are also called Disciples
          of Christ, and Campbellites.
      (b) One of a sect (called Christian Connection) of
          open-communion immersionists. The Bible is their only
          authoritative rule of faith and practice.
          [1913 Webster]

   Note: In this sense, often pronounced, but not by the members
         of the sects, kr[imac]s"chan.
         [1913 Webster]

WordNet (r) 3.0 (2006):

Christian
    adj 1: relating to or characteristic of Christianity; "Christian
           rites"
    2: following the teachings or manifesting the qualities or
       spirit of Jesus Christ [ant: unchristian]
    n 1: a religious person who believes Jesus is the Christ and who
         is a member of a Christian denomination

The Devil's Dictionary (1881-1906):

CHRISTIAN, n.  One who believes that the New Testament is a divinely
inspired book admirably suited to the spiritual needs of his neighbor.
One who follows the teachings of Christ in so far as they are not
inconsistent with a life of sin.

    I dreamed I stood upon a hill, and, lo!
    The godly multitudes walked to and fro
    Beneath, in Sabbath garments fitly clad,
    With pious mien, appropriately sad,
    While all the church bells made a solemn din --
    A fire-alarm to those who lived in sin.
    Then saw I gazing thoughtfully below,
    With tranquil face, upon that holy show
    A tall, spare figure in a robe of white,
    Whose eyes diffused a melancholy light.
    "God keep you, strange," I exclaimed.  "You are
    No doubt (your habit shows it) from afar;
    And yet I entertain the hope that you,
    Like these good people, are a Christian too."
    He raised his eyes and with a look so stern
    It made me with a thousand blushes burn
    Replied -- his manner with disdain was spiced:
    "What!  I a Christian?  No, indeed!  I'm Christ."
                                                                  G.J.