mis·fea·sance /mis-'fēz-əns/ n [Anglo-French misfesance, from Middle French mesfaire to do wrong, from mes- wrongly + faire to make, do, from Latin facere]: the performance of a lawful action in an illegal or improper manner; specif: the performance of an official duty in an improper or unlawful manner or with an improper or corrupt motive compare malfeasance, nonfeasance
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.