Enjoin Law and Legal Definition
Enjoin is an order by a court or official authority to do or refrain from doing an act. To enjoin is to prohibit by judicial order or issue an injunction against. For example, a federal court recently found that federal courts have jurisdiction over a suit to enjoin state officials from enforcing a state law on the ground that federal law preempts the state law. Ammex, Inc. v. Cox, 351 F. 3d 697 (6th Cir. 2003). The court referred to "the Supreme Court's repeated holdings that federal jurisdiction extends to suits to enjoin state enforcement on federal preemption and comparable grounds."