whistle blow

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.

   Synonyms:

   tattle, tell on

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