counterdemonstrator
/ˌkaʊntərˈdɛmənˌstreɪtər/
noun
- A person who takes part in a counterdemonstration, protesting against another protest.
- The police asked the counterdemonstrators to move to a designated area across the street.
- Each counterdemonstrator carried a sign expressing their opposing view.
- The counterdemonstrators shouted slogans to drown out the original protesters.