Untighten is a common word used in everyday conversations to describe the action of loosening something that is tight. However, there are various synonyms that can be used instead of untighten to provide more variety and depth to your language. These synonyms include slacken, loosen, ease up, relax, unwind, unclench, unbind, release, and unfasten. Each of these words carries a slightly different connotation, so choosing the appropriate synonym can help you add more color and clarity to what you're trying to convey. The next time you want to use the word untighten, consider using one of these synonyms instead for a more polished and effective communication.