You will never see an "idiom" mentioned in the official IELTS band descriptors. In fact, you will see "the skillful use of idiomatic language" as a requirement to score 7 and more. IE (idiomatic expressions) encompass all phrases that are not translated word-by-word: idioms, phrasal verbs, collocations, turn of phrase.
Remember that on IELTS you have to showcase your natural English, and native speakers do not use idioms a lot naturally. However, they use IE a... more🤪 IDIOMS ON IELTS - HOW TO USE?
You will never see an "idiom" mentioned in the official IELTS band descriptors. In fact, you will see "the skillful use of idiomatic language" as a requirement to score 7 and more. IE (idiomatic expressions) encompass all phrases that are not translated word-by-word: idioms, phrasal verbs, collocations, turn of phrase.
Remember that on IELTS you have to showcase your natural English, and native speakers do not use idioms a lot naturally. However, they use IE as a whole much more often. In fact, Cambridge illustrates that the following phrases are also idiomatic language:
🔎On the contrary
🔎Last but not least
🔎In the long term
🔎One step at a time
These are acceptable forms of IE alongside with phrasal verbs that one can safely use in Writing and Speaking, while phrases like "it rains cats and dogs" or "it costs an arm and leg" must be definitely avoided.