"Brass-bound" refers to something that is firmly or tightly bound with brass, or even having brass inlaid or decorated on it. The antonyms for "brass-bound" would therefore be "unadorned," "plain," or "simple". These antonyms indicate a lack of decorative or ornamental features, as opposed to something that is embellished with brass. Some more antonyms for "brass-bound" could include "unencumbered," "light," or "unweighted," which convey a sense of minimalism and unburdened freedom, as opposed to something that is weighed down or encumbered by decorative features. Therefore, depending on the context, the antonyms for "brass-bound" may vary, but they typically suggest the absence of decorative brass elements.