NOUN (3)

1. a person who is professionally engaged in the analysis and interpretation of works of art;

2. anyone who expresses a reasoned judgment of something;

3. someone who frequently finds fault or makes harsh and unfair judgments;

The Collaborative International Dictionary of English v.0.48:

Critic \Crit"ic\ (kr[i^]t"[i^]k), n. [L. criticus, Gr.
   kritiko`s, a critic; prop., an adj. meaning able to discuss,
   from kri`nein to judge, discern. See Certain, and cf.
   Critique.]
   1. One skilled in judging of the merits of literary or
      artistic works; a connoisseur; an adept; hence, one who
      examines literary or artistic works, etc., and passes
      judgment upon them; a reviewer.
      [1913 Webster]

            The opininon of the most skillful critics was, that
            nothing finer [than Goldsmith's "Traveler"] had
            appeared in verse since the fourth book of the
            "Dunciad."                            --Macaulay.
      [1913 Webster]

   2. One who passes a rigorous or captious judgment; one who
      censures or finds fault; a harsh examiner or judge; a
      caviler; a carper.
      [1913 Webster]

            When an author has many beauties consistent with
            virtue, piety, and truth, let not little critics
            exalt themselves, and shower down their ill nature.
                                                  --I. Watts.
      [1913 Webster]

            You know who the critics are? the men who have
            failed in literature and art.         --Beaconsfield.
      [1913 Webster]

   3. The art of criticism. [Obs.] --Locke.
      [1913 Webster]

   4. An act of criticism; a critique. [Obs.]
      [1913 Webster]

            And make each day a critic on the last. --Pope.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Critic \Crit"ic\, a.
   Of or pertaining to critics or criticism; critical. [Obs.]
   "Critic learning." --Pope.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Critic \Crit"ic\, v. i. [Cf. F. critiquer.]
   To criticise; to play the critic. [Obs.]

   Syn: critique.
        [1913 Webster]

              Nay, if you begin to critic once, we shall never
              have done.                          --A. Brewer.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Critique \Cri*tique"\ (kr[i^]*t[=e]k"), n. [F. critique, f., fr.
   Gr. kritikh` (sc. te`chnh) the critical art, from kritiko`s.
   See Critic.]
   [1913 Webster]
   1. The art of criticism. [Written also critic.] [R.]
      [1913 Webster]

   2. A critical examination or estimate of a work of literature
      or art; a critical dissertation or essay; a careful and
      thorough analysis of any subject; a criticism; as, Kant's
      "Critique of Pure Reason."
      [1913 Webster]

            I should as soon expect to see a critique on the
            poesy of a ring as on the inscription of a medal.
                                                  --Addison.
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   3. A critic; one who criticises. [Obs.]
      [1913 Webster]

            A question among critiques in the ages to come.
                                                  --Bp. Lincoln.
      [1913 Webster]

WordNet (r) 3.0 (2006):

critic
    n 1: a person who is professionally engaged in the analysis and
         interpretation of works of art
    2: anyone who expresses a reasoned judgment of something
    3: someone who frequently finds fault or makes harsh and unfair
       judgments

The Devil's Dictionary (1881-1906):

CRITIC, n.  A person who boasts himself hard to please because nobody
tries to please him.

    There is a land of pure delight,
        Beyond the Jordan's flood,
    Where saints, apparelled all in white,
        Fling back the critic's mud.

    And as he legs it through the skies,
        His pelt a sable hue,
    He sorrows sore to recognize
        The missiles that he threw.
                                                            Orrin Goof