Smattered, which means to sprinkle or spread something in small quantities, has a variety of antonyms. To apply or spread something in a larger quantity or more evenly, you might use words like aspersed, doused, drenched, flooded, or soaked. Alternatively, for the opposite of smattered in terms of coverage, you might consider words such as blanketed, covered, overrun, or swathed. To imply the opposite of smattered in terms of consistency, words like kneaded, massaged, mixed, or stirred could be used to indicate a more thorough or thorough blending of elements. The context of your writing will ultimately determine which antonyms of smattered are appropriate to use.