| n. | 1. | The state of being fast and firm; firmness; fixedness; security; faithfulness. |
| 2. | A fast place; a stronghold; a fortress or fort; a secure retreat; a castle; | |
| 3. | Conciseness of style. | |
| 4. | The state of being fast or swift. |
| Noun | 1. | fastness - a rate (usually rapid) at which something happens; "the project advanced with gratifying speed" |
| 2. | fastness - the quality of being fixed in place | |
| 3. | fastness - a strongly fortified defensive structure Synonyms: stronghold |