1879, William Tecumseh Sherman, Address to the Michigan Military AcademyWar is at best barbarism...It's glory is all moonshine.
An error in language use within a single word, such as a mispronunciation.
2002, Hyman, Bad Grammar in Context, New England Classical Journal, 29, p. 94-101In the jargon of the ancient grammarian, penacilin would be a barbarism.