The word "art mid-air" does not have an exact antonym since it is not a common word or phrase. However, some possible opposites can be derived from the meaning of the two constituent words. Art refers to creative expression or the application of skill and imagination to produce something visually or intellectually stimulating. Thus, its opposite might be dullness, banality, or lack of skill or imagination. Mid-air, on the other hand, means a state of suspension or being in the air without support. Its antonyms could be grounded, anchored, or propped up. Combining these opposite concepts may lead to new phrases such as "mundane anchorage" or "innovative suspension.