Peremptory Challenge
One of a limited number of special jury challenges given to each party before trial. A peremptory challenge results in the exclusion of a potential juror without the need for any reason or explanation - unless the opposing party presents a prima facie argument that this challenge was used to discriminate on the basis of race, ethnicity, or sex.
The goal is to balance the power to remove jurors, eliminate biases, and ensure a fair trial.
Each side in a case has a certain number of challenges that can be used without giving a reason. If a juror is excused, this does not imply something bad and does not mean the juror is not competent.
See Batson challenge.