grammatical

grammatical
/grəˈmætɪkl; ɡrə`mætɪkl/ adj
of, about or in accordance with the rules of grammar 语法的; 符合语法规则的
    a grammatical treatise 语法论文
    a grammatical error 语法错误
    That sentence is not grammatical. 那个句子语法不通.

牛津英汉双解词典