The Collaborative International Dictionary of English v.0.48:

Disclaimer \Dis*claim"er\, n.
   1. One who disclaims, disowns, or renounces.
      [1913 Webster]

   2. (Law) A denial, disavowal, or renunciation, as of a title,
      claim, interest, estate, or trust; relinquishment or
      waiver of an interest or estate. --Burrill.
      [1913 Webster]

   3. A public disavowal, as of pretensions, claims, opinions,
      and the like. --Burke.
      [1913 Webster]

Jargon File (4.4.4, 14 Aug 2003):

disclaimer
 n.

   [Usenet] Statement ritually appended to many Usenet postings
   (sometimes automatically, by the posting software) reiterating the
   fact (which should be obvious, but is easily forgotten) that the
   article reflects its author's opinions and not necessarily those of
   the organization running the machine through which the article
entered
   the network.


Moby Thesaurus II by Grady Ward, 1.0:

65 Moby Thesaurus words for "disclaimer":
   abjuration, abjurement, abnegation, abrogation,
   absolute contradiction, annulment, contradiction,
   contrary assertion, contravention, controversion, countering,
   crossing, declension, declination, declinature, declining, denial,
   deprivation, disaffirmation, disagreement, disallowance, disavowal,
   disclamation, disobedience, disowning, disownment, disproof,
   dissent, expatriation, forswearing, gainsaying, holding back,
   impugnment, nay, negation, negative, negative answer, nix, no,
   nonacceptance, noncompliance, nonconsent, nonobservance,
   nullification, palinode, palinody, recantation, refusal,
   refutation, rejection, reneging, renouncement, renunciation,
   repudiation, retention, retractation, retraction, revocation,
   revokement, thumbs-down, turndown, unsaying, unwillingness,
   withdrawal, withholding