What is the legal term for evidence that was obtained improperly?

The term that refers to evidence obtained improperly is exclusionary evidence. This legal concept is rooted in the principle that evidence acquired in violation of a person's constitutional rights, such as through unlawful search and seizure, is not permissible in court. The rationale behind this is to deter law enforcement from engaging in illegal practices that infringe on individual rights, thereby maintaining the integrity of the legal system.

Admissible evidence refers to evidence that a court allows to be presented to the jury or judge, while circumstantial evidence is indirect evidence that implies a fact but does not directly prove it. Primarily circumstantial evidence is a subset of circumstantial evidence, but it does not address the legality of how evidence was obtained. Thus, exclusionary evidence appropriately describes evidence that should not be considered due to improper procurement.