fastness Meaning, Definition & Usage

  1. noun a rate (usually rapid) at which something happens
    speed; swiftness.
    • the project advanced with gratifying speed
  2. noun the quality of being fixed in place as by some firm attachment
    secureness; fixity; fixedness; fixture.
  3. noun a strongly fortified defensive structure
    stronghold.

WordNet

Fast"ness noun
Etymology
AS. fæstnes, fr. fæst fast. See Fast, a.
Definitions
  1. The state of being fast and firm; firmness; fixedness; security; faithfulness.
    All . . . places of fastness [are] laid open. Sir J. Davies.
  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. Ascham.
  4. The state of being fast or swift.

Webster 1913