The word "ought" is a modal verb commonly used to express obligation or duty. It suggests something that is expected, recommended, or morally right to do. When someone says you "ought" to do something, they are implying that you should do it based on rules, advice, or ethical beliefs.
The word "ought" comes from the Old English word "āht," which means "possession" or "to own." Over time, it evolved to indicate moral obligation and necessity.