activist
ac·tiv·ist
/ˈæktıvıst/ noun , pl -ists [ count ]
: a person who uses or supports strong actions (such as public protests) to help make changes in politics or society
Antiwar activists were protesting in the streets.
an environmental activist
political activists
ac·tiv·ism /ˈæktıˌvızəm/ noun [ noncount ]
political activism