The word "art case" refers to a container or box that is used to carry or store art supplies. Its antonyms could include "artless" or "unimaginative," indicating a lack of creativity or originality. Other antonyms could include "disarray" or "disorganization," which suggest a lack of order or method in the storage of art supplies. Another antonym could be "minimalist," which implies a preference for simplicity and fewer materials. "Barren" or "sterile" could also be antonyms for "art case" as they suggest a lack of artistic inspiration or ideas.