A more thorough explanation:

Definition: When a legal action is no longer relevant or necessary to resolve because the issue has already been resolved or there is no longer a live dispute for a court to resolve.

For example, if someone sues their neighbor for cutting down a tree on their property, but the neighbor has already replanted the tree and apologized, the case would be considered moot because there is no longer a live dispute for the court to resolve.

It is important to note that federal courts only have the authority to resolve actual disputes, so if a case becomes moot, the court cannot continue to hear it.

Examples of Supreme Court cases that have dealt with mootness include Arizonans for Official English v. Arizona and Hicklin v. Orbeck.