sport one's oak

verb1

1. •
   (old-fashioned) To close one's door (originally the outer door of one's set of rooms in a college) as an indication that visitors are not welcome.

   • My rooms are pleasant enough,[…], and separated from all mankind by a great, iron-clamped, outer door, my oak, which I sport when I go out, or want to be quiet; […] — 1859