Entry 2 senses Webster, 1913 Protester /prōt'-ĕsˌ-tẽr/ · Pro·test·er · IPA /pɹəˈtɛstəɹ/ 01 n. One who protests; one who utters a solemn declaration. 1. One who protests; one who utters a solemn declaration. 2. One who protests a bill of exchange, or note.(Law)