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]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "retaliate":
   alternate, atone, avenge, bandy, be quits with, change,
   come back at, commute, compensate, cooperate, counter,
   counterchange, cover, do penance, even the score, exchange,
   expiate, fill up, get back at, get even with, give, give and take,
   give in exchange, give in return, hit back at, indemnify,
   interchange, launch a vendetta, logroll, make amends,
   make compensation, make good, make up for, pay back, permute,
   reciprocate, recompense, rectify, repay, requite, respond, retort,
   return, return the compliment, revenge, set right, strike back,
   swap, switch, take revenge, trade, transpose