What is an idiom?
An idiom is a fixed expression whose overall meaning cannot be deduced from the individual words. Idioms are deeply embedded in everyday English and are essential for natural-sounding speech and writing.
Fixed form
Cannot usually be changed word by word: "kick the bucket" not "kick a bucket".
Figurative meaning
The meaning is figurative, not literal: "bite the bullet" = endure something painful.
Register matters
Many idioms are informal. Avoid them in very formal academic writing.
This lesson covers 60 high-frequency idioms across 11 topics. Use Browse & search to explore them, then test yourself with three activities.