Solecism
SOL'ECISM, noun
1. Impropriety in language, or a gross deviation from the rules of syntax; incongruity of words; want of correspondence or consistency. A barbarism may be in one word; a solecism must be of more.
2. Any unfitness, absurdity or impropriety. Cesar, by dismissing his guards and retaining his power, committed a dangerous solecism in politics.