A false, dirty or slanderous story used for political advantage, usually about a candidate seeking political office.
In 1940 the Chicago Tribune offered this definition: “A roorback is a false report about some alleged misdeed in a candidate’s past, often based on forged evidence, circulated in the final days of a campaign. It is timed for climactic effect when the candidate will not be able to expose the fraud before the voters go to the polls.”
According to Museum of Hoaxes, the term is derived from Baron von Roorback, the invented author of an imaginary book, Roorback’s Tour Through the Western and Southern States, from which a passage was purportedly quoted in an attempt to defame Tennessee Gov. James K. Polk in the 1844 presidential election.