The word "more gravelly" refers to a rough, harsh, and uneven texture or sound. The antonyms for this word could be smoother, slicker, even, or polished. A surface that is smooth and polished has a uniform texture with no rough patches or bumps. It could refer to a singing voice that is refined, gentle, or melodious. Similarly, a sleek and shiny car has no rough spots or scratches on its surface. The antonyms for "more gravelly" represent characteristics that are opposite to the roughness and unevenness of gravel, such as smoothness, evenness, and refinement.