noun

• (film, theater) An extra or walk-on, often non-speaking, in a film or play; a spear carrier.
  "[A] minor actor or supernumerary often has a better opportunity to watch great actors than the great actors themselves."
• (zoology) An animal which has not formed a pair bond and is therefore single.
  "The best evidence so far that social supernumeraries are physically capable of bettering their lot concerns not rodents but birds."
• (Roman Catholicism) A married man or woman who is a secular member of Opus Dei, a Roman Catholic religious institution.
  "“Supernumeraries”, the bulk of Opus Dei members, can marry and live in their own homes, with slightly fewer spiritual obligations."

adj

• Beyond the prescribed or standard amount or number; excess, extra.
  "a supernumerary nipple; a supernumerary tooth"