(PROH-test-tor): A person who objects to something. Protesters are very public and loud about their opinions. In the Middle East, many protesters have become violent.

someone who participates in a public display of group feeling

One who protests; one who utters a solemn declaration.

a person who dissents from some established policy

an interested party to challenge the evaluation of its own proposal where there is a reasonable possibility that the proposal would be in line for award if the protest were sustained

One who protests a bill of exchange, or note.