agrammatical

adjective

agram·​mat·​i·​cal (ˌ)ā-grə-ˈma-ti-kəl 

: not conforming to the rules of grammar : ungrammatical

The agrammatical nature of the sentence leaves its meaning unclear …

—US Official News

Anyone who has had the misfortune of reading a printed copy of an electronic health record knows that it is often an agrammatical, incomprehensible mess.

—Lawrence R. Huntoon

One's own eyes widen a little as this strange narrative unfolds in a prose that seems initially to be as untidy and agrammatical as subway graffiti.

—Anthony Quinn

Word History

First Known Use

1873, in the meaning defined above