There is a lot of similarity between phrasal verb and idiom. The essential difference between the two, however, is that a phrasal verb is a verb whose meaning is modified by a preposition, or adverb, or both, but which still functions as a verb. An idiom, on the other hand, is more like a saying or an expression that is specific to a culture. While a lot of idioms are formed using phrasal verb, many are not.
Using idioms correctly and comfortably in speech and writing shows mastery and fluency in the language. Idioms add liveliness to language; without idioms, language may be correct, but it may be dull. Knowledge of idioms is particularly important for understanding spoken English, as in informal situations, people often use idioms as shorthand for lengthy explanations.
- Idiom: To pay through the nose
Meaning: To pay more for something than its actual worth
- Idiom: On the rocks
Meaning: Near failure or defeat