This idiom refers to exposing wrongdoing, corruption, or misconduct, often by an insider, as if sounding a whistle to alert others. It conveys the act of revealing hidden truths, typically used in professional, political, or ethical contexts to describe courageous or risky disclosures. The phrase carries a tone of urgency, morality, or betrayal, reflecting cultural values of justice and the human tendency to confront or expose malfeasance. Its imagery, rooted in signaling, evokes a sharp call to attention, resonating in scenarios like corporate scandals or public exposés. The idiom underscores the tension between loyalty and truth, making it a powerful metaphor for ethical accountability.

The phrase originated in early 20th-century Britain, tied to sports referees blowing whistles to stop play for fouls, extended metaphorically to halting misconduct. Its earliest recorded use appears in *The Times* (1910s), describing a worker ‘blowing the whistle’ on factory violations. The idiom gained traction during the 1970s, particularly in the U.S., amid high-profile whistleblower cases like Watergate, with *The Washington Post* using it extensively. Its spread was amplified by legal protections for whistleblowers and media, notably in films like *All the President’s Men* (1976). Its adoption across English-speaking cultures stems from its vivid imagery and relevance to ethical dilemmas.