term:

Misfeasance

misfeasance 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

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.