Not breaching any constraints of the grammar, or morpho-syntax, of the relevant language. / Of or pertaining to grammar.

metagrammar

(linguistics) (of language) The state or attribute of obeying the rules of grammar; grammatical correctness.

plural of grammaticality

Synonym of grammaticalize (“to make grammatical”). / Synonym of grammaticalize (“to to cause (something) to be required by the rules of grammar”).

grammatical

Third-person singular simple present indicative form of grammatize

Synonym of grammaticalization

in a grammatical manner / concerning grammar

(obsolete) A principle of grammar; a grammatical rule.