Malfeasance, misfeasance and non-feasance distinctions define wrongful acts, omissions, public-law duties, liability and remedial consequences. Definitions distinguish three modes of wrongful official conduct: malfeasance is the commission of an act that is positively unlawful; misfeasance is the improper performance of a lawful act; and non-feasance is the omission or total failure to perform a duty that ought to be performed. Stroud cautions against treating misfeasance as a separate wrongful act and rejects non-feasance as excusing liability for certain public-way nuisances.