D defs.my
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. 1.
    One who protests; one who utters a solemn declaration.
  2. 2.
    One who protests a bill of exchange, or note.(Law)