The phrase "retaliatory response" means taking action or giving a reaction in response to an attack, harm, or provocation inflicted upon you, with the intent of getting back at the person or group who caused it. Full definition
We're «waiting for reaction from the European Union and reaction from the Chinese in terms retaliatory responses.» (cnbc.com)
Each side believes it a sign of weakness to permit any violence to occur without a retaliatory response. (religion-online.org)
There have been calls for the UK to act immediately in order to stop the free movement of workers; however such an act would be contrary to EU and international law and may well prompt a retaliatory response from other EU Member States. (europeanlawblog.eu)