Source : Webster's Revised Unabridged Dictionary (1913)

Insult \In*sult"\, v. t. [imp. & p. p. {Insulted}; p. pr. & vb.
   n. {Insulting}.] [F. insulter, L. insultare, freq. fr.
   insilire to leap into or upon; pref. in- in, on + salire to
   leap. See {Salient}.]
   1. To leap or trample upon; to make a sudden onset upon.
      [Obs.] --Shak.

   2. To treat with abuse, insolence, indignity, or contempt, by
      word or action; to abuse; as, to call a man a coward or a
      liar, or to sneer at him, is to insult him.

Insulting \In*sult"ing\, a.
   Containing, or characterized by, insult or abuse; tending to
   insult or affront; as, insulting language, treatment, etc. --
   {In*sult"ing*ly}, adv.

   Syn: Insolent; impertinent; saucy; rude; abusive;
        contemptuous. See {Insolent}.

Source : WordNet®

insulting
     adj 1: expressing offensive reproach [syn: {abusive}, {opprobrious},
             {scornful}, {scurrilous}]
     2: expressing extreme contempt [syn: {contemptuous}, {disdainful},
         {scornful}]