The antonyms for the word "un-diffused" are numerous. Diffused means to spread out, scatter or disperse something. Therefore, the antonyms for "un-diffused" could be concentrated, centralized, condensed, focused or converged. In other words, if something is not "un-diffused," it is not scattered, disorganized or spread out in all directions. Instead, it is concentrated and has direction. For example, light can be diffused, making it soft and gentle, or concentrated, making it bright and powerful. Similarly, a person's words can be diffused, meaning they are unclear and confusing, or focused, meaning they are precise and clear.