retaliation UK /ɹiˌtæl.iˈeɪ.ʃən/US /ɹɪˌtæl.iˈeɪ.ʃən/ noun1 •Violent or otherwise punitive response to an act of harm or perceived injustice; a hitting back; revenge.Hamas knew there would be massive retaliations. — 2009 formsretaliations