The Collaborative International Dictionary
malefeasance
Malfeasance \Mal*fea"sance\, n. [F. malfaisance, fr. malfaisant injurious, doing ill; mal ill, evil + faisant doing, p. pr. of faire to do. See Malice, Feasible, and cf. Maleficence.] (Law) The doing of an act which a person ought not to do; evil conduct; an illegal deed. [Written also malefeasance.]
Wiktionary
malefeasance
n. (obsolete form of malfeasance English)