idiomatic

Short definition from Wiktionary

Adjective

1. 1
   Pertaining or conforming to idiom, the natural mode of expression of a language.
2. 2
   Resembling or characteristic of an idiom.
3. 3
   Using many idioms.
4. 4
   Relating to parts or pieces which are written both within the natural physical limitations of the instrument and human body and, less so or less often, the styles of playing used on specific instruments.

Noun

1. 1
   Synonym of idiom.