Ungrammatical

[ʌngrə'mætɪk(ə)l] or ['ʌngrə'mætɪkl]

(adj.) not grammatical; not conforming to the rules of grammar or accepted usage .

Inputed by Conrad--From WordNet

adj. not according to the rules of grammar.—adv. Ungrammat′ically.

Edited by Hugh

In the best French which he could muster, and which was in sooth of a very ungrammatical sort, Jos besought the hussar to tell his tale. William Makepeace Thackeray. Vanity Fair.
Ungrammatical twaddler, was it, sir? Charles Dickens. The Pickwick Papers.

Edited by Hugh