The word "out-burst" typically refers to a sudden and intense release of emotions or actions. Some possible antonyms for this term might include words like 'calm', 'control', 'restraint', 'peacefulness', or 'repression'. Calmness refers to being in control of emotions and maintaining a sense of peace. Control implies a measured approach to behavior, while restraint refers to holding back impulses. Peacefulness suggests being in a serene state of mind, while repression entails keeping intense feelings tightly contained. Antonyms for 'out-burst' are useful terms to have in one's vocabulary, as they can describe a range of emotions and behaviors that contrast with sudden and chaotic outbursts.