Definitions for "Whistle blower"
Employee who publicly reports illegal activities going on inside his/her company.
an informant who exposes wrongdoing within an organization in the hope of stopping it; "the law gives little protection to whistleblowers who feel the public has a right to know what is going on"; "the whistleblower was fired for exposing the conditions in mental hospitals"
an insider who exposes corruption or abuse by his colleagues, often suffering retaliation as a result
an individual who discloses unlawful acts against the wishes of vested interests who seek to cover them up