General synonyms:
* Conciseness
* Shortness
* Terseness
* Compactness
* Succinctness
* Pithiness
More specific synonyms:
* Conciseness: Emphasizes the use of few words.
* Terseness: Emphasizes the use of sharp, pointed language.
* Pithiness: Emphasizes the use of meaningful and impactful words.
* Laconic: Implies a quiet or restrained style of communication.
* Abrupt: Suggests a sudden or unexpected end.
* Curt: Implies a rude or dismissive tone.
The best synonym for brevity will depend on the specific context.