Antonyms for the word "conniption fit" include peace, calmness, serenity, tranquility, and composure. These words describe a state of being that is exactly the opposite of the exasperation and fury that characterizes a conniption fit. They suggest a state of mind that is collected and unruffled, and convey a message of stability, poise, and level-headedness. Instead of reacting with anger, a person experiencing the opposite of a conniption fit would be able to approach a situation with a cool head and clearer judgment, offering a more productive and practical response.