The Collaborative International Dictionary
Misjoinder
Misjoinder \Mis*join"der\, n. (Law)
An incorrect union of parties or of causes of action in a
procedure, criminal or civil.
--Wharton.
Wiktionary
misjoinder
n. (context legal English) An incorrect union of parties or of causes of action in a procedure in criminal or civil court.
Wikipedia
Misjoinder
In legal procedure (both civil and criminal), misjoinder refers to a wrongful joinder.
Misjoinder of causes of action, or counts, consists in joining several demands to enforce substantive rights of recovery that are distinct and contradictory.
Misjoinder of parties consists in joining as plaintiffs or defendants persons who have conflicting interests, or who were not involved in the same transaction or event.