Whistle-blower (noun)

1. A person who exposes illegal or unethical practices under the guise of anonymity.
2. Someone who reveals information about misconduct within an organization.

Origin:

Late 20th century; earliest use found in the washington post (washington, d.c.). from whistle-blow + -er.

Examples:

1. The investigation into the corrupt police department was initiated by a whistle-blower.
2. The whistle-blower reported the company's fraudulent activities to the authorities.
3. The company tried to silence the whistle-blower, but their actions only attracted more attention.
4. The whistle-blower was praised for their bravery in coming forward.
5. The public has a right to know about any wrongdoings, and that's why we need more whistle-blowers.