The Collaborative International Dictionary of English v.0.48:

Libellee \Li`bel*lee"\, n. (Law)
      (a) The party against whom a libel has been filed; --
          corresponding to defendant in a common law action.
      (b) The defendant in an action of libel.
          [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

Defendant \De*fend"ant\, n.
   1. One who defends; a defender.
      [1913 Webster]

            The rampiers and ditches which the defendants had
            cast up.                              --Spotswood.
      [1913 Webster]

   2. (Law) A person required to make answer in an action or
      suit; -- opposed to plaintiff. --Abbott.
      [1913 Webster]

   Note: The term is applied to any party of whom a demand is
         made in court, whether the party denies and defends the
         claim, or admits it, and suffers a default; also to a
         party charged with a criminal offense.
         [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Defendant \De*fend"ant\ (d[-e]*f[e^]nd"ant), a. [F.
   d['e]fendant, p. pr. of d['e]fendre. See Defend.]
   1. Serving, or suitable, for defense; defensive. [Obs.]
      [1913 Webster]

            With men of courage and with means defendant.
                                                  --Shak.
      [1913 Webster]

   2. Making defense.
      [1913 Webster]

WordNet (r) 3.0 (2006):

defendant
    n 1: a person or institution against whom an action is brought
         in a court of law; the person being sued or accused [syn:
         defendant, suspect] [ant: complainant, plaintiff]

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "defendant":
   accessory, accused, bitter-ender, brawler, correspondent, diehard,
   disputant, dissentient, dissident, intransigent, irreconcilable,
   last-ditcher, libelee, litigant, litigationist, litigator,
   naysayer, negativist, noncooperator, objector, obstructionist,
   obstructive, opposer, oppositionist, panel, parties litigant,
   party, plaintiff, prisoner, protester, quarreler, resister,
   respondent, scrapper, suitor, suspect, witness, wrangler



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

DEFENDANT. A party who is sued in a personal action. Vide Demandant; Parties
to Actions; Pursuer; and Com. Dig. Abatement, F; Action upon the case upon
assumpsit, E, b; Bouv. Inst. Index, h.t.
      2. At common law a defendant cannot have judgment to recover a sum of
money of the plaintiff. But this rule is, in some cases, altered by the act
of assembly in Pennsylvania, as by the. Act of 1705, for defalcation, by
which he may sue out a sci. fac. on the record of a verdict for a sum found
in his favor. 6 Binn. Rep. 175. See Account 6.