Source : Webster's Revised Unabridged Dictionary (1913)

Effrontery \Ef*front"er*y\, n.; pl. {Effronteries}. [F.
   effronterie, fr. effront['e] shameless, fr. L. effrons,
   -ontis, putting forth the forehead, i. e., barefaced,
   shameless; ex + frons the forehead. See {Front}.]
   Impudence or boldness in confronting or in transgressing the
   bounds of duty or decorum; insulting presumptuousness;
   shameless boldness; barefaced assurance.

         Corruption lost nothing of its effrontery. --Bancroft.

   Syn: Impudence; sauciness. See {Impudence}.

Source : WordNet®

effrontery
     n : audacious (even arrogant) behavior that you have no right
         to; "he despised them for their presumptuousness" [syn: {presumption},
          {presumptuousness}, {assumption}]