When something is in error, it means it is incorrect or inaccurate. However, there are many other ways to express this idea using synonyms. For example, you could say that something is mistaken, faulty, flawed, invalid, untrue, mistaken, misguided, or erroneous. Other synonyms might include inaccurate, mistaken, mistaken, incorrect, wrong, problematic, confusing, or misleading. The key is to choose the right synonym for the specific context, depending on the level of seriousness or importance of the error in question. Whether it is a small mistake or a huge blunder, there are always alternative ways to convey the message that something is not quite right.