Other forms: misfeasances
Misfeasance happens when someone in authority uses her position to do something wrong. If a town's mayor uses his influence to get jobs for his family members, that's misfeasance.
One way to define misfeasance is "the wrongful exercise of lawful authority." In other words, the power or authority is legal and fair, but the way it's being used is harmful. If a judge, sheriff, city councilor, or other public official acts in a way they know will cause harm, it's considered misfeasance. This legal term comes from an Old French word, mesfaire, "to misdo," which combines the roots mes-, "wrongly," and faire, "to do."