The phrase "shuts mouth" is often used synonymously with "silences," "quells," "mutes," "hushes," or "suppresses." These words all describe the action of restraining oneself from speaking or causing someone else to stop talking. "Silences" is the most commonly used term and implies a complete cessation of speech. "Quells" often implies a forceful or authoritative act of shutting someone down. "Mutes" refers to the ability to make something soundless, while "hushes" suggests a gentler, shushing action. "Suppresses" implies a deliberate effort to hold something back, whether it be words or emotions. Ultimately, all of these synonyms describe the act of intentionally closing one's mouth to stop speaking.