Aortic Arch Syndrome is a medical condition affecting the aorta, a major artery supplying blood to the body. However, there are no direct antonyms for this term as it is a specific medical condition. Antonyms are words that are opposite in meaning to a particular word. For instance, antonyms for happy could include sad, miserable, or unhappy. Similarly, antonyms for hot include cold, freezing, or cool. Therefore, while there are no direct antonyms for Aortic Arch Syndrome, we can use words like healthy, normal, or functioning to refer to the opposite of this medical condition.