What term is used in the law when both parties are equally responsible for an illegal agreement?

Pari delicto

Explanation:

The Pari delicto is a legal principle that means both parties are legally and equally responsible for making an illegal agreement or executing crime due to common interest. The term is common for the relief that is being denied to both parties under the civil proceedings because of equal responsibility of commission of wrongdoing by both parties. This legal principle ensures the equitable defense.