idiomatic

mastery
UK /ˌɪd.iː.əˈmat.ɪk/ US /ˌɪd.i.əˈmæt.ɪk/adjnoun

card 1 of 6 · synonym

Which word is closest in meaning to 'idiomatic' in this sentence?

We warned the students that 'beating around the bush' is an idiomatic phrase with a specific meaning they should memorize.