Nila wrote:I am trying to guess if this idiom have a meaning similar to "stop something" or "to make ilegal".
I think it could be "to stop something".
Some of the crowd try to put the black players off their game with racist chants such as monkey noises. However, new UEFA rules could blow the whistle on this.
This comes from a team sports analogy. In team sports where there is a referee, such as basketball or American football, the coach will "blow the whistle" literally, with a real whistle, when he sees a player breaking a rule.
In other contexts, the idea is that a person who blows the whistle is revealing somebody's wrong behavior or even a crime.
People who blow the whistle are sometimes referred to as "whistleblowers
", and yet their efforts are often not rewarded. It's so bad that there is a government agency to protect whistleblowers: Whistleblower Protection Program