The phrase "be wrong" is a common expression used to indicate a mistake or error. However, there are a variety of synonyms that can be used to convey the same meaning. One such synonym is "err," which means to make a mistake or be incorrect. Another option is "misjudge," which suggests a failure to accurately evaluate a situation. "Mistake" and "fault" are two additional synonyms that can be used to describe an error. Finally, the phrase "off the mark" can be used to indicate that a person's assessment or understanding is incorrect. Choosing the right synonym will depend on the context and tone of the situation.