dungeon /(dŭn"jŭn)/

dun·geon

dungeon

n.
  1. A close, dark prison, commonly, under ground, as if the lower apartments of the donjon or keep of a castle, these being used as prisons.
    Down with him even into the deep dungeon.
    — Tyndale.
    Year after year he lay patiently in a dungeon.

Dungeon

v. t.
  1. To shut up in a dungeon.