The Collaborative International Dictionary of English v.0.48:

Litigant \Lit"i*gant\, a. [L. litigans, -antis, p. pr. of
   litigare: cf. F. litigant. See Litigate.]
   Disposed to litigate; contending in law; engaged in a
   lawsuit; as, the parties litigant. --Ayliffe.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Litigant \Lit"i*gant\, n.
   A person engaged in a lawsuit.
   [1913 Webster]

WordNet (r) 3.0 (2006):

litigant
    n 1: (law) a party to a lawsuit; someone involved in litigation;
         "plaintiffs and defendants are both litigants" [syn:
         litigant, litigator]

The Devil's Dictionary (1881-1906):

LITIGANT, n.  A person about to give up his skin for the hope of
retaining his bones.