Antonyms for the phrase "most keyed up" are words that express calmness, relaxation, and serenity. Some antonyms could be "tranquil," "composed," "relaxed," "unperturbed," or "subdued." If someone is most keyed up, they are usually full of anxiety, stress, and tension. However, the antonyms for this phrase suggest the opposite, where individuals are at peace and completely calm. For instance, they might display a serene demeanor or a tranquil disposition. The antonyms for "most keyed up" describe the state of having a relaxed mind and a stress-free lifestyle, which is beneficial for mental and physical well-being.