An agreement which cannot be performed is known as a void agreement. This type of agreement is considered invalid and unenforceable by law.

There are several reasons why an agreement may be void. One reason is if the subject matter of the agreement is illegal or against public policy. For example, if two parties entered into an agreement to sell illegal drugs, that agreement would be void.

Another reason an agreement may be void is if one of the parties lacks the capacity to enter into the agreement. For example, if a minor entered into an agreement to purchase a car, that agreement would be void because minors are not legally able to enter into contracts.

Additionally, an agreement may be void if it is made under duress or coercion. For example, if one party threatened physical harm to the other party if they did not agree to a certain contract, that agreement would be void.

It is important to note that a void agreement is different from a voidable agreement. A voidable agreement is one that may be rescinded by one of the parties if certain conditions are met. For example, if a party was induced to enter into an agreement through fraud, they may be able to rescind the agreement.

In conclusion, an agreement which cannot be performed is known as a void agreement. It is important to understand the reasons why an agreement may be void in order to ensure that all agreements entered into are valid and enforceable. As a professional, it is important to use accurate and informative language when discussing legal concepts to provide value to readers.