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.
      [1913 Webster]

   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.
      [1913 Webster]

   3. One given to fault-finding; a censurer.
      [1913 Webster]

            Nor can the most circumspect attention, or steady
            rectitude, escape blame from censors who have no
            inclination to approve.               --Rambler.
      [1913 Webster]

   4. A critic; a reviewer.
      [1913 Webster]

            Received with caution by the censors of the press.
                                                  --W. Irving.
      [1913 Webster]

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"

Moby Thesaurus II by Grady Ward, 1.0:

126 Moby Thesaurus words for "censor":
   abbreviate, abridge, annotator, asphyxiate, belittler, black out,
   bleach, blip, blot out, blue-pencil, bottle up, bowdlerize, cancel,
   captious critic, carper, caviler, censurer, choke off,
   clamp down on, clean up, cognoscente, commentator, commenter,
   common scold, connoisseur, conscience, conscientiousness, cork,
   cork up, crack down on, critic, criticaster, criticizer, critickin,
   criticule, cross out, crush, cut, cut out, damp down, delete,
   drown, edit, edit out, editor, erase, ethical self, excise,
   expunge, expurgate, extinguish, faultfinder, frondeur, gag, grace,
   hold down, hugger-mugger, hush, hush up, hush-hush, inner arbiter,
   inward monitor, jump on, keep down, keep under, kill,
   literary critic, man of letters, momus, monopolist, moral censor,
   muckraker, muffle, muzzle, narrow, nitpicker, omit, pettifogger,
   pour water on, protectionist, purge, purify, put down, quash,
   quell, quench, quibbler, repress, rescind, restrain, restrict,
   restrictionist, reviewer, rub out, scholiast, scold, screen, shush,
   shut down on, silence, sit down on, sit on, smash, smellfungus,
   smother, social conscience, social critic, squash, squelch, stanch,
   stifle, strangle, strike, strike off, strike out, stultify, subdue,
   suffocate, superego, suppress, tender conscience, textual critic,
   throttle, twinge of conscience, voice of conscience, void