noun

1. a violation of the conventional usage, grammar, etc. of a language; ungrammatical use of words (Ex.: “We done it” for “We did it”)
2. a violation of good manners; breach of etiquette
3. a mistake or impropriety

Etymology: L soloecismus < Gr soloikismos < soloikos, speaking incorrectly, after Soloi, city in Cilicia, whose dialect was a corrupt form of Attic