Source : Webster's Revised Unabridged Dictionary (1913)

Libel \Li"bel\, v. t. [imp. & p. p. {Libeled} (-b[e^]ld) or
   {Libelled}; p. pr. & vb. n. {Libeling} or {Libelling}.]
   1. To defame, or expose to public hatred, contempt, or
      ridicule, by a writing, picture, sign, etc.; to lampoon.

            Some wicked wits have libeled all the fair. --Pope.

   2. (Law) To proceed against by filing a libel, particularly
      against a ship or goods.

Libel \Li"bel\ (l[imac]"b[e^]l), n. [L. libellus a little book,
   pamphlet, libel, lampoon, dim. of liber the liber or inner
   bark of a tree; also (because the ancients wrote on this
   bark), paper, parchment, or a roll of any material used to
   write upon, and hence, a book or treatise: cf. F. libelle.]
   1. A brief writing of any kind, esp. a declaration, bill,
      certificate, request, supplication, etc. [Obs.] --Chaucer.

            A libel of forsaking [divorcement].   --Wyclif
                                                  (Matt. v. 31).

   2. Any defamatory writing; a lampoon; a satire.

   3. (Law) A malicious publication expressed either in print or
      in writing, or by pictures, effigies, or other signs,
      tending to expose another to public hatred, contempt, or
      ridicule. Such publication is indictable at common law.

   Note: The term, in a more extended sense, includes the
         publication of such writings, pictures, and the like,
         as are of a blasphemous, treasonable, seditious, or
         obscene character. These also are indictable at common
         law.

   4. (Law) The crime of issuing a malicious defamatory
      publication.

   5. (Civil Law & Courts of Admiralty) A written declaration or
      statement by the plaintiff of his cause of action, and of
      the relief he seeks.

Libel \Li"bel\ (l[imac]"b[e^]l), v. i.
   To spread defamation, written or printed; -- with against.
   [Obs.]

         What's this but libeling against the senate? --Shak.

         [He] libels now 'gainst each great man.  --Donne.

Source : WordNet®

libel
     v : print slanderous statements against; "The newspaper was
         accused of libeling him"
     [also: {libelling}, {libelled}]

libel
     n 1: a tort consisting of false and malicious publication printed
          for the purpose of defaming a living person
     2: the written statement of a plaintiff explaining the cause of
        action (the defammation) and any relief he seeks
     [also: {libelling}, {libelled}]