blow the whistle

Verb

blow the whistle (third-person singular simple present blows the whistle, present participle blowing the whistle, simple past blew the whistle, past participle blown the whistle)

1. (idiomatic, usually) To disclose information to the public or to appropriate authorities concerning the illegal or socially harmful actions of a person or group, especially a corporation or government agency.
   • In some jurisdictions, it is illegal to fire a person for blowing the whistle on an employer.
   • In recent months, tech journalists at The New York Times have received quite a few such messages, sent by people who claim to have unlocked hidden knowledge with the help of ChatGPT, which then instructed them to blow the whistle on what they had uncovered.2025 June 13, Kashmir Hill, “They Asked ChatGPT Questions. The Answers Sent Them Spiraling.”, in The New York Times, →ISSN

   Synonyms:

   tattle, tell on

2. (team sports) To make a piercing sound which signals a referee's action or the end of a game.