The antonyms for the word "most seething" are calm, peaceful, and serene. Calm is a state of tranquility, where everything is in order and there's no chaos or disturbance. Peaceful means a state of quietness and serenity, where there's no hostility, harm, or disturbance. Serene is also a state of tranquility, where there's a feeling of calmness and peacefulness in the environment. These antonyms present an environment very different from the one that is seething with activity or anger. It's a place of peace and calmness that's devoid of any stress, chaos or anger.