solecism

1. An element of speech or writing that is incorrect grammatically.
Like barbarisms, solecisms are possible according to each of the four categories of change. (Silva Rhetoricae)

2. 48. PURITY ALSO REQUIRES CONFORMITY TO GRAMMAR AND IDIOM.
In order to write pure English, it is further necessary that there be no departure from those forms of speech which are established by the laws of grammar or sanctioned by the best idiomatic usage. The violation of either of these is called a solecism. (De Mille)

3. Solecism.—This is the general term that includes violations of the rules of grammar and rhetoric, unidiomatic phrases, and mistaken expressions. Solecisms are treated in this volume under the specific designations of the rules they contravene; but it can hardly be said that the list is complete, or could be made so, for any writer may at any time perpetrate a new soliecism. (Johnson, 259-260)

4. A solecism is a construction at war with the grammar of the language. Solecisms can be found occasionally on the pages of even our best writers. They are slips resulting from carelessness, but are not on that account venial. They consist mainly in the use of the wrong modes, tenses, and numbers of verbs, the wrong numbers, genders, and case of pronouns, and in the use of adjectives for adverbs and of adverbs for adjectives. (Kellog, 97)

1. "Me fail English? That's unpossible" (added by Allan McDougall)

3. Thomas Gray, in his seventy-fifth letter to Mason, says: "I much like Dr. Lowth's Grammar; it is concise, clear, and elegant. He has selected his solecisms from all the best writers of our tongue." (Johnson, 260)