counterdemonstrator
coun·ter·de·monstrator
noun
1.
someone who demonstrates in opposition to another demonstration
Origin
From counter- + demonstrator.
Related words
Broader terms
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.