What does “dépasser les bornes” mean in French?

A borne is a boundary marker, the stone or post that shows where one property ends. Dépasser les bornes means to go past it: to behave in a way that is out of line. You can say it about a rude joke, an angry parent, or a bill that has grown absurd. Its opposite is the adjective sans bornes (“boundless”), as in une patience sans bornes.

The Radio-Canada report opens with parents at youth hockey games who, after a loss, dépassent les bornes and end up in open conflict, which is why Hockey Québec is weighing a mandatory good-manners course for them. The phrase is neutral in register, so it works in a news story or at the dinner table. A close cousin is dépasser les limites, which is a little more literal and a little more common in France.