misfeasance

Misfeasance is the improper performance of a lawful act, resulting in harm. It is distinct from malfeasance, which involves the commission of an unlawful act, and from nonfeasance, which is the failure to act when there is a duty to do so. Misfeasance may arise from negligence, incompetence, or a breach of professional standards, where the actor had a duty to perform safely or correctly but failed to do so.

In tort law, misfeasance can support liability where the actor’s improper performance causes damage, even though the underlying act itself was permissible. For example, a contractor who lawfully undertakes a project but installs defective infrastructure due to careless workmanship may be liable for misfeasance. In public administration, misfeasance in public office refers to improper performance of a duty by a public official, potentially giving rise to civil liability if it causes loss.

Some jurisdictions distinguish misfeasance from malfeasance by focusing on the nature of the act (lawful but performed improperly) and from nonfeasance by focusing on the presence of an attempted act. The term is also used in professional contexts to describe negligent handling of duties that are legally permissible, such as procedural errors that breach standard care without an illegal act.