"Against the law" is a phrase commonly used to describe an action that is illegal or prohibited. However, there are numerous synonyms that can be used to describe such actions. Terms such as illegal, unlawful, illicit, criminal, and prohibited are all interchangeable with "against the law". Similarly, words like improper, wrongful, unauthorized, and prohibited can also be used to describe actions that are not in compliance with the law. While these synonyms may differ slightly in meaning or connotation, they all convey the same idea that a particular action is not permissible under the law. Using these synonyms can add variety and nuance to one's writing or speech.