Русско-англо-русский юридический словарь

"A public officer commits malfeasance by corruptly exceeding the scope of his or her authority and commits misfeasance by acting within the scope of his authority but doing so corruptly." (Sewell v. State, 239 Md. App. 571, 601-02 (2018))

The court then went on to use yet another definition, "malfeasance is the doing of an act which an officer had no legal right to do at all and that when an officer, through ignorance, inattention, or malice, does that which they have no legal right to do at all, or acts without any authority whatsoever, or exceeds, ignores, or abuses their powers, they are guilty of malfeasance." (Wikipedia)

"Although it is a singular offense, the crime of official misconduct covers three modes of behavior: (1) misfeasance, (2) malfeasance, and (3) nonfeasance. Nonfeasance is 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; and malfeasance is the doing of an act which a person ought not to do at all." (Sewell v. State, 239 Md. App. 571, 601-02 (2018))

As of year’s end, 87 sitting or former public servants had been charged with corruption. This included 14 cases of fraud committed using official position, 10 cases of misappropriation or embezzlement using official position, eight cases of nonviolent misuse of official powers for personal gain, eight cases of nonviolent exceeding of official powers, one case of illegal participation in entrepreneurial activities while taking advantage of official position, 30 cases of bribery, and 16 cases of creating a fraudulent official document for personal gain. (U.S. Department of State)

malfeasance: intentionally doing something either legally or morally wrong which one had no right to do. It always involves dishonesty, illegality or knowingly exceeding authority for improper reasons. (Law.com)