The Collaborative International Dictionary of English v.0.48:

Censor \Cen"sor\, n. [L. censor, fr. censere to value, tax.]
   1. (Antiq.) One of two magistrates of Rome who took a
      register of the number and property of citizens, and who
      also exercised the office of inspector of morals and
      conduct.
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   2. One who is empowered to examine manuscripts before they
      are committed to the press, and to forbid their
      publication if they contain anything obnoxious; -- an
      official in some European countries.
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   3. One given to fault-finding; a censurer.
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            Nor can the most circumspect attention, or steady
            rectitude, escape blame from censors who have no
            inclination to approve.               --Rambler.
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   4. A critic; a reviewer.
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            Received with caution by the censors of the press.
                                                  --W. Irving.
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WordNet (r) 3.0 (2006):

censor
    n 1: someone who censures or condemns
    2: a person who is authorized to read publications or
       correspondence or to watch theatrical performances and
       suppress in whole or in part anything considered obscene or
       politically unacceptable
    v 1: forbid the public distribution of ( a movie or a newspaper)
         [syn: ban, censor]
    2: subject to political, religious, or moral censorship; "This
       magazine is censored by the government"