The phrase "most stone deaf" is typically used to describe someone who is completely deaf. However, there are many synonyms that can be used to describe the same thing. Words like "profoundly deaf," "totally deaf," and "completely deaf" are all good examples of synonyms that can be used. Other phrases that might be used to describe someone who is most stone deaf include "absolutely deaf," "utterly deaf," or "heedless to sound." It's important to choose the right synonym based on the specific context in which you are using the word. By using the right terminology, you can ensure that your message is clear and effective.