Most reverberant refers to the quality of sound that echoes and vibrates through a space for a long time. The antonyms for this word can vary depending on the context. Some antonyms that could be used include quiet, muted, dull, muffled, or dead. These words imply a lack of resonance or reverberation, and suggest that sound is absorbed rather than reflected. Other antonyms that convey a different meaning altogether might include clear, distinct, or concise. These words suggest a sense of precision or clarity, rather than a prolonged echo or resonance. Ultimately, the appropriate antonyms for most reverberant will depend on the tone and context of the discussion.