Source : Webster's Revised Unabridged Dictionary (1913)

Arrogant \Ar"ro*gant\, a. [F. arrogant, L. arrogans, p. pr. of
   arrogare. See {Arrogate}.]
   1. Making, or having the disposition to make, exorbitant
      claims of rank or estimation; giving one's self an undue
      degree of importance; assuming; haughty; -- applied to
      persons.

            Arrogant Winchester, that haughty prelate. --Shak.

   2. Containing arrogance; marked with arrogance; proceeding
      from undue claims or self-importance; -- applied to
      things; as, arrogant pretensions or behavior.

   Syn: Magisterial; lordly; proud; assuming; overbearing;
        presumptuous; haughty. See {Magisterial}.

Source : WordNet®

arrogant
     adj : having or showing feelings of unwarranted importance out of
           overbearing pride; "an arrogant official"; "arrogant
           claims"; "chesty as a peacock" [syn: {chesty}, {self-important}]