noun
grammaticality
Linguistics term referring to whether a sentence conforms to the rules of a grammar.
この文の文法性を判断してください。
Please judge the grammaticality of this sentence.
適格性 is a broader term for 'well-formedness' in linguistics, sometimes used interchangeably with 文法性.
Compound of 文法 (grammar) and 性 (property, -ness). A straightforward modern technical term.