A more thorough explanation:

Adversary procedure is a legal system where two opposing parties present their case before an independent decision-maker. This system is commonly used in the Anglo-American legal system, especially in criminal cases. It is also known as the adversary system or accusatorial procedure.

For example, in a criminal trial, the prosecution and defense present their evidence and arguments to a judge or jury, who then make a decision based on the merits of each side's case. The parties are free to challenge each other's evidence and arguments, and the decision-maker acts as a neutral referee.

The adversary procedure is different from the inquisitorial system, which is used in some other countries. In an inquisitorial system, the judge takes an active role in investigating the case and gathering evidence, rather than relying on the parties to present their own evidence.