In his speech marking the end of the Afghanistan war, begun soon after the 9/11 attacks on 11 September 20 years ago, Joe Biden complained that the former Afghan president had fled amid “corruption and malfeasance”, which might have sounded rather an orotund accusation. From the French faire (to do), “misfeasance” entered English in the early 17th century via a legal treatise by none other than Francis Bacon, who, as well as being a pioneering philosopher of science, was also attorney general and lord chancellor. “Misfeasance” was swiftly joined by the alternative “malfeasance”, exchanging the Germanic prefix mis- for the French mal-, for bad or evil. They both literally mean wrongdoing, but have usually been reserved specifically for the unlawful exercise of authority, or other misdeeds in public office, of which there has been no shortage of examples among, say, American presidents. More generally malfeasance can mean any kind of wrongdoing, and “corporate malfeasance” is the modern term for what often seems to be more common than corporate bienfeasance, which is not a word as there is so little call for it. Optimistically, Ralph Waldo Emerson wrote: “Nature turns all malfaisance [sic] to good.” But he didn’t give a timeframe. Steven Poole’s A Word for Every Day of the Year is published by Quercus. This article was amended on 10 September 2021. The prefix mis- has Germanic origins, not Greek as an earlier version said.