adversarial UK /ˌæd.vəˈsɛə.ɹi.əl/US /ˌæd.vɚˈsɛɚ.i.əl/adjective 2forms 2phrases 1 adjective2 •Characteristic of, or in the manner of, an adversary; combative, hostile, opposed.The White Paper therefore aims to tackle complexity rather then ownership of the railways, and to eliminate "the adversarial relationships between operators, suppliers, NR and government". — 2021 •In which issues are tried through the presentation of evidence and argument by adverse parties, with no or limited inquiry by the court's own initiative.Canada uses an adversarial system of criminal justice, whereas France uses an inquisitorial model. formsmore adversarial · most adversarial Phrases with adversarial adversarial collaborationAny of a class of study designs in which scientists with conflicting theories work together with others who are neutral or agnostic about those theories, and this team runs an experiment to test the theories empirically and thus find out whether one of the theories is contradicted by the evidence found.