The term "art matter of" can be broken down into two parts. Art, in this context, refers to creative expression, while matter of denotes something that is of concern or importance. Antonyms for this phrase could be things like unimportant or irrelevant, as they convey the opposite meaning. Alternatively, for just the word "art", antonyms could include things like science or logic, which represent more analytical fields. And for "matter of", antonyms could include trivial or insignificant, which convey a sense of unimportance or lack of concern. By using antonyms, we can better understand the nuances of language and how to express concepts with precision.