Solecism
Solecism , noun
[French solécisme, Latin soloecismus, Greek soloikismo`s, from soloiki`zein to speak or write incorrectly, from so`loikos speaking incorrectly, from the corruption of the Attic dialect among the Athenian colonists of So`loi in Cilicia.]
1.
An impropriety or incongruity of language in the combination of words or parts of a sentence; esp., deviation from the idiom of a language or from the rules of syntax.
A barbarism may be in one word; a solecism must be of more.
2.
Any inconsistency, unfitness, absurdity, or impropriety, as in deeds or manners.
Caesar, by dismissing his guards and retaining his power, committed a dangerous solecism in politics.
The idea of having committed the slightest solecism in politeness was agony to him.