behalf

When you act on behalf of someone, you do something for them as their representative. Imagine a lawyer speaking on behalf of a client in court: the lawyer voices the client’s needs and defends their interests. You might also donate to a charity on behalf of a friend, or sign a petition on behalf of a community group. In modern English, on behalf of is the normal form, while in behalf of is rare and often old-fashioned.

The word indicates acting in the interest of another person or group—carrying out an action for them as their representative. It is usually used in phrases that follow a preposition, most commonly on behalf of. In the phrase, the speaker is not saying they personally replace the other person so much as they are acting with their authority, support, or permission.

Think of a spokesperson who speaks on behalf of a company; they deliver messages and present the organization’s official position. Or think of a parent signing a permission slip on behalf of a child. In both cases, there is usually trust and clear authority, since the person is acting with another party’s interests in mind.

It is important to note that "behalf" is used for actions done for someone, not to them. For instance, you wouldn't say, "The doctor treated me on behalf of my illness." However, you would say, "I am accepting this award on behalf of the entire team."