To determine the synonym of the word "Brief," we start by understanding its meaning. "Brief" signifies something that lasts for a short period of time or is concise in nature. Next, we examine the given options:
- Long: Opposite in meaning as it implies expansive duration or length.
- Quick: Refers to speed rather than duration or conciseness, thus not quite synonymous.
- Short: Aligns with "Brief," as both suggest something limited in duration or concise.
- Slow: Indicates a decreased pace rather than brevity, so it isn't synonymous.
Based on this analysis, the word "Short" acts as the best synonym for "Brief" because both involve the concept of limited duration or succinctness.