Functus Officio

appointed official whose term in office has ended (Latin)

Functus officio, Latin for "having performed his office," is a legal term used to indicate that a public official, court, governing body, or statute retains no legal authority because his or its duties and functions have been completed. The term is most commonly used by a higher court as a justification for vacating or overruling all or part of a lower court's opinion. For example, if a United States federal court decides that a law comports with the requirements of due process, the court cannot then attempt to strike the law simply because the law is unwise because the court's due process determination renders it functus officio in the particular case.
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Latin: an officer or agency whose mandate has expired either because of the arrival of an expiry date or because an agency has accomplished the purpose for which it was created. - (read more on Functus officio)
  

Lat. This term is applied to something which once had life and power, but which now has no virtue whatsoever. E.g., When an agent has completed the business with which he was entrusted, his agency is functus officio.
   

This entry contains material from Bouvier's Legal Dictionary, a work published in the 1850's.