Fastness

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

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.