Misfeasance Definition:

Improperly doing something which a person has the legal right to do.

In Proksch v. Bettendorf, 218 Iowa 1376 (1934), the Supreme Court of Iowa adopted these words:

"Nonfeasance ... means the omission of an act which a person ought to do. Misfeasance is the improper doing of an act which a person might lawfully do. Malfeasance is the doing of an act which a person ought not to do at all."

To legal theorists, negligence can be arguably divided into msfeasance and, in limited cases, nonfeasance whereas malfeasance is an intentional tort.