The term "runs off the mouth" refers to a person who talks excessively without thinking about their words. Some antonyms for this phrase are "chooses words carefully," "speaks thoughtfully," or "talks with restraint." These phrases indicate someone who is mindful of the impact of their speech and takes care to express themselves in a clear and reasoned manner. Other antonyms could include "reserves judgment," "listens carefully," or "keeps quiet." These expressions suggest a person who is thoughtful, reflective, and cautious about speaking, rather than someone who simply blurts out whatever comes to mind. By contrast, those who "run off the mouth" may be seen as impulsive, careless, or thoughtless in their communication.