A more thorough explanation:

Reargument is the act of presenting additional arguments to a court, usually an appellate court, after initial arguments have already been heard. These additional arguments may suggest that a controlling legal principle has been overlooked. It is different from a rehearing, which is a new hearing of a case.

For example, if a party in a court case believes that the court did not consider an important legal principle in its initial decision, they may request a reargument to present additional arguments and evidence to support their position.

Reargue is the verb form of reargument.