The Collaborative International Dictionary of English v.0.48:

Indignation \In`dig*na"tion\, n. [F. indignation, L. indignatio.
   See Indign.]
   [1913 Webster]
   1. The feeling excited by that which is unworthy, base, or
      disgraceful; anger mingled with contempt, disgust, or
      abhorrence. --Shak.
      [1913 Webster]

            Indignation expresses a strong and elevated
            disapprobation of mind, which is also inspired by
            something flagitious in the conduct of another.
                                                  --Cogan.
      [1913 Webster]

            When Haman saw Mordecai in the king's gate, that he
            stood not up, nor moved for him, he was full of
            indignation against Mordecai.         --Esther v. 9.
      [1913 Webster]

   2. The effect of anger; punishment. --Shak.
      [1913 Webster]

            Hide thyself . . . until the indignation be
            overpast.                             --Is. xxvi.
                                                  20.

   Syn: Anger; ire wrath; fury; rage. See Anger.
        [1913 Webster]

WordNet (r) 3.0 (2006):

indignation
    n 1: a feeling of righteous anger [syn: indignation,
         outrage]