When we want to express the idea of keeping quiet or staying silent, the phrase "hold one's tongue" instantly comes to mind. However, sometimes using the same phrase repeatedly can get tiresome. If you want to add a little variety to your vocabulary, there are plenty of synonyms you can use instead. You could say "shut up," "be quiet," "keep mum," "zip it," "bite one's tongue," or "hold one's peace." Each of these phrases conveys the same idea - stopping the flow of words out of your mouth. Whatever synonym you choose, just remember that there are times when it's better to keep your opinions to yourself.