The Court becomes functus officio when its task or the task before it is completely performed. Functus officio, a Latin term, means “task performed”. It means, as this Court stated in MOHAMMED v. HUSSEINI (1998) 14 NWLR (pt. 584) 108 at pages 163 164, that the judge or the Court cannot give a decision twice or make an order on the matter twice. In other words, once a Court or judge makes a final order on a matter, it (or he) no longer has the competence or jurisdiction to give another decision or order on the same matter.
— E. Eko, JSC. FRN v Maishanu (2019) – SC.51/2015