Fastness

Fast·ness

Fastness

n.
  1. The state of being fast and firm; firmness; fixedness; security; faithfulness.
    All . . . places of fastness [are] laid open.
  2. A fast place; a stronghold; a fortress or fort; a secure retreat; a castle; as, the enemy retired to their fastnesses in the mountains.
  3. Conciseness of style. [Obs.]
  4. The state of being fast or swift.