OXFORD DICTIONARY
Grammatical, adj.
1 a of or relating to grammar. b determined by grammar, esp. by form or inflection (grammatical gender).
2 conforming to the rules of grammar, or to the formal principles of an art, science, etc.
grammatically adv. grammaticalness n.
F grammatical or LL grammaticalis f. L grammaticus f. Gk grammatikos (as GRAMMAR)
THESAURUS
Grammatical
adjectival, adverbial, attributive, conjunctive, copulative, correct, descriptive, formal, functional, glossematic, glottochronological, grammatic, graphemic, intransitive, lexicographic, lexicological, lexicostatistical, lingual, linguistic, linking, metalinguistic, morphological, morphophonemic, nominal, participial, philological, phonemic, phonetic, phonological, postpositional, prepositional, pronominal, psycholinguistic, semantic, structural, substantive, syntactic, tagmemic, transitive, verbal