What does "grammatical" mean?

Not breaching any constraints of the grammar, or morpho-syntax, of the relevant language.

How do you pronounce "grammatical"?

Pronounced //ɡɹəˈmætɪkəl//.

Common synonyms include: ablative, adjectival, adverbial, adverbial label, attributive, auxiliary verb.

/ɡɹəˈmætɪkəl/ adj

adj ·Moderate ·High school level

Adjective

1
Not breaching any constraints of the grammar, or morpho-syntax, of the relevant language.
"Your writing in English is not grammatical enough for publication, so we will hire an editor to fix it where necessary while preserving the intended meaning."
2
Of or pertaining to grammar.
"The writing was measured for both grammatical complexity and accuracy factors."

Adjective

1
conforming to the rules of grammar or usage accepted by native speakers wordnet
2
of or pertaining to grammar wordnet

"Your composition is free from all grammatical mistakes."

From Middle French grammatical, from Latin grammaticālis.