Misjoinder is a legal term that refers to the improper joining of two or more parties in a lawsuit. It can also refer to the improper joining of two or more claims or causes of action in a single lawsuit. There are several synonyms for the word misjoinder, including misjoining, improper joinder, erroneous joinder, and flawed joinder. These synonyms all describe the same concept, which is the inclusion of parties or claims in a lawsuit that do not belong together. Misjoinder can result in confusion, delay, and unnecessary expense for all parties involved. It is important to avoid misjoinder and ensure that all parties and claims are properly joined before beginning a lawsuit.