adversarial
adj.adj. describing a situation where two sides are in a fight or competition. In law, it means that the two parties in a case are working against each other to win.
adj. characterised by opposition or conflict between two or more parties. In a legal context, it describes a system or process where the parties are treated as opponents rather than as partners in a shared process.
The legal system is adversarial, so both sides try to win.
In an adversarial environment, the defense attorney must constantly challenge the prosecution's evidence to protect their client.
The shift from an inquisitorial to an adversarial system of justice requires a significant change in how evidence is presented and how judges manage courtroom dynamics.
Probably from adversary + -al