The Collaborative International Dictionary of English v.0.48:

Retaliate \Re*tal"i*ate\, v. t. [imp. & p. p. Retaliated; p.
   pr. & vb. n. Retaliating.] [L. retaliatus, p. p. of
   retaliare to retaliate; pref. re- re- + a word akin to talio
   talion, retaliation. Cf. Talion.]
   To return the like for; to repay or requite by an act of the
   same kind; to return evil for (evil). [Now seldom used except
   in a bad sense.]
   [1913 Webster]

         One ambassador sent word to the duke's son that his
         visit should be retaliated.              --Sir T.
                                                  Herbert.
   [1913 Webster]

         It is unlucky to be obliged to retaliate the injuries
         of authors, whose works are so soon forgotten that we
         are in danger of appearing the first aggressors.
                                                  --Swift.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Retaliate \Re*tal"i*ate\, v. i.
   To return like for like; specifically, to return evil for
   evil; as, to retaliate upon an enemy.
   [1913 Webster]

WordNet (r) 3.0 (2006):

retaliate
    v 1: take revenge for a perceived wrong; "He wants to avenge the
         murder of his brother" [syn: revenge, avenge,
         retaliate]
    2: make a counterattack and return like for like, especially
       evil for evil; "The Empire strikes back"; "The Giants struck
       back and won the opener"; "The Israeli army retaliated for
       the Hamas bombing" [syn: retaliate, strike back]