whistle blower
/ˈwɪsəl ˌbloʊər/
noun
- A person who tells the public or someone in authority about dishonest or illegal activities within an organization.
- After the scandal, the whistle-blower was praised for her courage.
- The whistle-blower revealed that the company was dumping toxic waste into the river.
- Laws protect whistle-blowers from being fired or punished for reporting wrongdoing.