形容詞 grammatical:

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

1. Having a grammatical structure that allows of two interpretations; equivocal.
   歧義的，模棱兩可的一種語法結(jié)構(gòu)可以有兩種解釋的; 模棱兩可的
2. Don't think you can learn grammatical rules like you learn multiplication tables.
   不能像記乘法表那樣記語法規(guī)則。
3. You've made several grammatical mistakes in the composition.
   你的作文中犯了幾處語法錯(cuò)誤。
4. In general, a grammatical clause contain a subject and a predicate.
   一般說來，一個(gè)合乎文法的子句包含有主詞與述語。

gram.mat.i.cal

adj.（形容詞）
Of or relating to grammar.
屬于或關(guān)于語法的
Conforming to the rules of grammar:
遵循語法規(guī)則的：
例句：
a grammatical sentence.
語法正確的句子

來源：
Late Latin grammatic3lis
后期拉丁語 grammatic3lis
from Latin grammaticus
源自 拉丁語 grammaticus
from Greek grammatikos [of letters] * see grammar
源自 希臘語 grammatikos [字母的] *參見 grammar

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