Adjective
not grammatical; not conforming to the rules of grammar or accepted usage
Source: WordNetYou can be a little ungrammatical if you come from the right part of the country. Robert Frost
A speaker may indicate dominance through arrogance using the phrase His shit don't stink (though ungrammatical, this is the accepted diction). Source: Internet
Fowler (1926), p. 559. In some cases, moving the adverbial creates an ungrammatical sentence or changes the meaning. Source: Internet
However, not only has no evidence been found of a river "Lo" predating the work where Peder Claussøn Friis first proposed this etymology, but the very name is ungrammatical in Norwegian: the correct form would have been Loaros (cf. Source: Internet
In Hausa it is ungrammatical to do the same with coordinating conjunctions. Source: Internet
For example, it would be ungrammatical to write "Mary was hugged her daughter" in order to show that Mary and her daughter shared a hug. Source: Internet