A more thorough explanation:

An exclusionary hearing is a pretrial hearing conducted to review and determine the admissibility of alleged illegally obtained evidence in a criminal case. During this hearing, the judge decides whether the evidence should be excluded from the trial because it was obtained in violation of the defendant's constitutional rights.

For example, if the police obtained evidence through an illegal search or seizure, the defense may request an exclusionary hearing to argue that the evidence should not be allowed in court. The judge will then hear arguments from both sides and make a decision on whether the evidence is admissible or not.