This means to tell someone something to help them stay safe. It is often about danger or problems.
I warn you about the wet floor.
They warned us of the big storm.
In sports, it means to officially tell a player about breaking a rule. It is a formal notice before stricter penalties.
The referee warned the player for rough play.
He was warned for breaking the sports rules.
This means to tell someone ahead of time about something bad that may happen. It helps people prepare or avoid problems.
They warned us days before the war began.
The guide warned about the hard journey ahead.
This meaning is about giving a formal warning to stop bad behavior or risk punishment. It is common in schools or workplaces.
The teacher warned the student about cheating.
You will be warned for breaking the rules again.
This means to give a sign or signal that something bad or important is going to happen.
The dark clouds warn of rain soon.
The bell warned the workers to stop.
This is a technical meaning used by police or security. It means to tell others that something is missing or stolen so they watch for it.
The police warned the stolen car to other stations.
They warned the lost phone across the city.