Meaning of “retaliate” - Learner’s Dictionary

retaliate

verb [ I ] us uk /rɪˈtælieɪt/

to do something bad to someone because they have done something bad to you:

They have threatened to retaliate against any troops that attack.
retaliation noun [ U ] us uk /rɪˌtæliˈeɪʃən/

They bombed the hotel in retaliation for the arrests.
retaliatory adjective us uk /rɪˈtæliətəri/

retaliatory measures

(Definition of “retaliate” from the Cambridge Learner’s Dictionary © Cambridge University Press)