solecism n.

"gross grammatical error" (as I done it for I did it); loosely "a small blunder in speech; any absurdity or incongruity, a violation of the conventional rules of society," 1570s, from French solécisme (16c.), from Latin soloecismus "mistake in speaking or writing," from Greek soloikismos "a speaking (Greek) incorrectly," from soloikos "speaking incorrectly, using provincialisms," also "awkward or rude in manners," anciently said to have originally meant "speaking like the people of Soloi," a Greek colony in Cilicia (modern Mezitli in Turkey), whose dialect the Athenians considered barbarous. Sometimes also solœcism. Related: Solecize; solecist; solecistic; solecistical.