idiomatic
adjective uk/ˌɪd.i.əˈmæt.ɪk/ us/ˌɪd.i.əˈmæt̬.ɪk/
习语的;成语的;合乎语言习惯的
containing or consisting of an idiom
"Bite the bullet" is an idiomatic expression that means to accept something unpleasant without complaining. bite the bullet 是个惯用表达法，意思是没有怨言地接受令人不快的事物。
（语言）自然地道的
containing expressions that are natural and correct
She was born in Italy but her English is fluent and idiomatic. 她出生在意大利，却讲一口流利地道的英语。