I think "syntactic" would be a single word for structure dependent, wrt linguistics: as in syntax as "The arrangement of words and phrases to create well-formed sentences in a language"
So either "non-syntactic" or "a-syntactic"? (However, I'm not sure if the latter is actually in the dictionary)!
Syntactic : of, relating to, or according to the rules of syntax or syntactics
Asyntactic :not syntactic, an asyntactic narrative