Definition of “rebellion” - English Dictionary. See all translations. uk ​ /rɪˈbel.i.ən/ us ​ /rɪˈbel.i.ən/. C1 violent action organized by a group of people who are trying to change the political system in their country: The government has brutally crushed the rebellion. › action against those in authority, against the rules, or against normal and accepted ways of behaving: