Webster's Revised Unabridged Dictionary · 1913

Malfeasance

Malfeasance , noun

[French malfaisance, from malfaisant injurious, doing ill; mal ill, evil + faisant doing, present participle of faire to do. See Malice, Feasible, and compare Maleficence.]

(Law) The doing of an act which a person ought not to do; evil conduct; an illegal deed.