The antonyms for the word "art acceptable" are numerous, but some of the most common include "unappealing", "unattractive", "unpleasant", "repulsive", "disgusting", "ugly", "offensive", "distasteful", "vulgar", and "inelegant". These words all convey a sense of negativity or dissatisfaction with the aesthetic qualities of art, suggesting that something fails to meet certain standards of beauty or taste. While what is considered "acceptable" or "good" art can, of course, vary depending on individual tastes and cultural contexts, these antonyms all imply a broad consensus that something is lacking in the visual or conceptual appeal of a particular work.