To pick a fight with a visiting lord is a solecism, but being caught that way would have put the solecism squarely on Minch's head…
-- Joel Rosenburg, Hour of the Octopus
The idea of having committed the slightest solecism in politeness, whether real or imaginary, was agony to him; for perhaps even guilt itself does not impose upon some minds so keen a sense of shame and remorse, as a modest, sensitive, and inexperienced youth feels from the consciousness of having neglected etiquette, or excited ridicule.
-- Sir Walter Scott, Waverly
Solecism was originally a toponym for people from the Greek city of Cilicia where a corrupt form of Greek was spoken. It came to mean "a mistake in speaking or writing" in Middle French in the 1500s. The sense of "a breach in manners" was recorded in the early 1600s.