grammatical

形容词 grammatical:

1. of or pertaining to grammar
   同义词：grammatic
2. conforming to the rules of grammar or usage accepted by native speakers
   同义词：well-formed

1. Having a grammatical structure that allows of two interpretations; equivocal.
   歧义的，模棱两可的一种语法结构可以有两种解释的; 模棱两可的
2. Don't think you can learn grammatical rules like you learn multiplication tables.
   不能像记乘法表那样记语法规则。
3. You've made several grammatical mistakes in the composition.
   你的作文中犯了几处语法错误。
4. In general, a grammatical clause contain a subject and a predicate.
   一般说来，一个合乎文法的子句包含有主词与述语。

gram.mat.i.cal

adj.（形容词）
Of or relating to grammar.
属于或关于语法的
Conforming to the rules of grammar:
遵循语法规则的：
例句：
a grammatical sentence.
语法正确的句子

来源：
Late Latin grammatic3lis
后期拉丁语 grammatic3lis
from Latin grammaticus
源自 拉丁语 grammaticus
from Greek grammatikos [of letters] * see grammar
源自 希腊语 grammatikos [字母的] *参见 grammar

【引伸】
grammat.ical.ity
grammat.ically
adv.（副词）