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]

WordNet (r) 3.0 (2006):

disclaimer
    n 1: (law) a voluntary repudiation of a person's legal claim to
         something
    2: denial of any connection with or knowledge of [syn:
       disavowal, disclaimer]

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



The Jargon File (version 4.4.7, 29 Dec 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.


The Free On-line Dictionary of Computing (30 December 2018):

disclaimer

    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 organisation running the computer
   through which the article entered the network.

   [Jargon File]

   (1995-07-30)


Bouvier's Law Dictionary, Revised 6th Ed (1856):

DISCLAIMER. This word signifies. to abandon, to renounce; also the act by
which the renunciation is made. For example, a disclaimer is the act by
which a patentee renounces a part of his title of invention,
     2. In real actions, a disclaimer of the tenancy or title is frequently
added to the plea of non tenure. Litt. Sec. 391. If the action be one in
which the demandant cannot recover damages, as formedon in the discender,
the demandant or plaintiff was bound to pray judgment, &c., and enter, for
thereby, he has the effect of his suit, et frustra fit per plura quod fieri
potest per pauciora. But, if the demandant can recover damages and is
unwilling to waive them, he should answer the disclaimer by averring that
the defendant is tenant of the land, or claims to be such as the writ
supposes, and proceed to try the question, otherwise he would lose his
damages. The same course may be pursued in the action of ejectment, although
in Pennsylvania, the formality of such a replication to the disclaimer is
dispensed with, and the fact is tried without it. 5 Watts, 70; 3 Barr, 367.
Yet, if the plaintiff is willing to waive his claim for damages, there is no
reason why he may not ask for judgment upon the disclaimer without trial,
for thereby he has the effect of his suit. Et frustra fit per plura, &c.



Bouvier's Law Dictionary, Revised 6th Ed (1856):

DISCLAIMER, estates. The act of a party by which be refuses to accept of an
estate which has been conveyed to him. Vide Assent; Dissent.
     2. It is said, that a disclaimer of a freehold estate must be in a
court of record, because a freehold shall not be divested by bare words, in
pais. Cruise, Dig. tit. 32, c. 2 6, s. 1, 2.
     3. A disclaimer of tenancy is the act of a person in possession, who
denies holding the estate from the person claiming to be the owner of it. 2
Nev. & M. 672. Vide 8 Vin.. Ab. 501; Coote, L. & T. 348, 375; F. N. B. 179
k; Bull. N. P. 96; 16 East, R. 99; 1 Man. & Gran. 135; S. C. 39 Eng. C. L.
Rep. 380, 385; 10 B. & Cr. 816; ow, N. P. Cas. 180; 2 Nov. & Man. 673; 1 C.
M. & R. 398 Co. Litt. 102, a.



Bouvier's Law Dictionary, Revised 6th Ed (1856):

DISCLAIMER, chancery pleading. The renunciation of the defendant to all
claims to the subject of the demand made by the plaintiff's bill.
     2. A disclaimer is distinct in substance from an answer, though
sometimes confounded with it, but it seldom can be put in without an answer
for if the defendant has been made a party by mistake, having had an
interest which be has parted with, the plaintiff may require an answer
sufficient to ascertain whether that is the fact or not. Mitf. Pl. 11, 14,
253; Coop. Eq. Pl. 309; Story, Eq. Pl. c. 17, Sec. 838 to 844; 4 Bouv. Inst.
n. 4211-14.