The term "art witness" simply refers to someone who testifies about art in a court of law. The antonyms for the word "art witness" could be anything that is not art or legal in nature. Some possible antonyms for "art witness" could be a sports enthusiast, a business professional, or a musician. These individuals have nothing to do with art or the legal system and therefore are completely unrelated to the term "art witness." It's important to remember that antonyms are words that have the opposite meanings of each other, and in the case of "art witness," there are many words that can be considered antonyms depending on the context in which the term is being used.