The Collaborative International Dictionary of English v.0.48:

Censorship \Cen"sor*ship\, n.
   The office or power of a censor; as, to stand for a
   censorship. --Holland.
   [1913 Webster]

         The press was not indeed at that moment under a general
         censorship.                              --Macaulay.
   [1913 Webster]

WordNet (r) 3.0 (2006):

censorship
    n 1: counterintelligence achieved by banning or deleting any
         information of value to the enemy [syn: censoring,
         censorship, security review]
    2: deleting parts of publications or correspondence or
       theatrical performances [syn: censoring, censorship]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "censorship":
   abbreviation, abridgment, bamboo curtain, barrier of secrecy,
   blackout, block, blockage, blocking, blue-penciling,
   bowdlerization, cancellation, censoring, crackdown, crushing,
   curtain, deletion, editing, erasure, expurgation, extinguishment,
   hush-up, inhibition, iron curtain, ironbound security,
   oath of secrecy, official secrecy, omission, pall,
   psychological block, putting down, quashing, quelling, quenching,
   repression, resistance, restraint, seal of secrecy, security,
   smashing, smothering, squashing, squelching, stifling, strangling,
   striking, subdual, suffocating, suppression, throttling, veil,
   veil of secrecy, wraps