Origin: Latin suffix -al
Grammatical has 3 different meanings across 1 category:
of or pertaining to grammar
"the grammatic structure of a sentence"
"grammatical rules"
"grammatical gender"
conforming to the rules of grammar or usage accepted by native speakers
"spoke in grammatical sentences"
Not breaching any constraints of the grammar, or morpho-syntax, of the relevant language.
"The teacher praised her essay for being grammatically flawless, noting that every sentence strictly followed the rules of English syntax without error."