idiom vs artistic style

idiom and artistic style both are nouns.

Word	Noun	Adjective	Verb	Adverb
idiom	Yes	No	No	No
artistic style	Yes	No	No	No

As nouns, idiom and artistic style are synonyms defined as:

idiom and artistic style: the style of a particular artist or school or movement

idiom (noun)	artistic style (noun)
the style of a particular artist or school or movement	the style of a particular artist or school or movement
the usage or vocabulary that is characteristic of a specific group of people
an expression whose meanings cannot be inferred from the meanings of the words that make it up
a manner of speaking that is natural to native speakers of a language