WordieWhat Is an Idiom?
Idiom: A fixed expression whose overall meaning cannot be worked out from the meanings of its individual words, such as spill the beans (reveal a secret) or under the weather (slightly ill).
Also known as: idiomatic expression
An idiom is a fixed expression whose meaning is more than the sum of its words. If someone says your exam will be a piece of cake, nobody is talking about dessert; if a colleague spills the beans, nothing gets dirty. You cannot work out an idiom from a dictionary entry for each word; you have to learn it as a whole, like a single vocabulary item.
Common English idioms and their meanings
| Idiom | Meaning | Example |
|---|---|---|
| break the ice | ease tension at the start of a meeting | He told a joke to break the ice. |
| under the weather | slightly ill | I'm feeling a bit under the weather today. |
| spill the beans | reveal a secret | Who spilled the beans about the party? |
| hit the nail on the head | describe something exactly right | You hit the nail on the head with that point. |
| bite the bullet | do something unpleasant but necessary | I finally bit the bullet and called the bank. |
| beat around the bush | avoid the main point | Stop beating around the bush and tell me. |
| let the cat out of the bag | reveal a secret by accident | She let the cat out of the bag about the merger. |
| once in a blue moon | very rarely | We only eat out once in a blue moon. |
| by and large | generally, on the whole | By and large, the reviews were positive. |
Idioms are not all equally opaque
Idioms sit on a scale of transparency:
- Transparent: the image explains itself. Play with fire, see the light, a breath of fresh air.
- Semi-transparent: the logic is visible once explained. Break the ice (cracking the frozen surface so ships can pass), bite the bullet.
- Opaque: no visible link. Kick the bucket, by and large, red herring.
They also vary in how fixed they are. You can say break the ice or the ice was broken, but the bucket was kicked loses the meaning "died." Some allow a slot: let the cat out of the bag stays fixed, while keep [someone] in the dark takes any object.
Idioms vs collocations vs phrasal verbs
All three are types of lexical chunk, but they differ in how predictable their meaning is:
| Type | Example | Meaning predictable from parts? |
|---|---|---|
| Collocation | heavy rain | yes; the challenge is choosing the right partner |
| Phrasal verb | give up, look after | sometimes; many are idiomatic |
| Idiom | kick the bucket | no |
Why idioms matter for vocabulary learners
Idioms are frequent in conversation, TV, sports commentary, headlines and business talk (move the goalposts, the ball is in your court). A reader who knows every word of a sentence can still miss its meaning entirely, which makes idioms a real comprehension problem. At the same time, they are tricky to produce: their wording is fixed, their register is usually informal, and some sound dated. Native speakers rarely say it's raining cats and dogs today, though textbooks love it.
How to learn idioms
- Learn them from real use. Save idioms you meet in articles, shows and conversations rather than working through long lists. Frequency in your own input is the best filter.
- Record the exact wording and an example sentence, including articles and prepositions: in the same boat, not on.
- Look up the origin when it is interesting. A story makes the idiom memorable, though many popular origin stories are unproven.
- Note the register and whether it is British, American or both.
- Prioritize understanding. Aim to recognize many idioms and actively use a smaller set you are sure of.
Common mistakes
- Changing a word. It's a piece of pie or spill the peas sounds like a joke.
- Mixing idioms. We'll cross that bridge when it comes home to roost.
- Overusing them in formal writing. One well-chosen idiom can work in an essay; five read like a textbook exercise.
- Translating idioms from your language. Most do not exist in English, or exist with a different image.
Frequently asked questions
What is an example of an idiom?
Break the ice means to make people feel more relaxed at the start of a meeting. Spill the beans means to reveal a secret. A piece of cake means something very easy. None of these meanings can be worked out word by word.
What is the difference between an idiom and a collocation?
In a collocation, each word keeps its usual meaning (heavy rain, make a mistake). In an idiom, the meaning of the whole is different from the sum of its parts (kick the bucket means to die).
Should English learners use idioms?
Learn to understand them first, since they are common in conversation, TV and journalism. Use them sparingly and only when you are sure of the exact wording and the register; a misused idiom stands out more than a plain sentence.
Are idioms the same in British and American English?
Mostly, but not always. British speakers say touch wood where Americans say knock on wood, and a storm in a teacup in British English is a tempest in a teapot in American English.
Related terms
Lexical Chunk
A group of words that speakers store and retrieve as a single prefabricated unit, such as by the way, as far as I know or I was wondering if you could.
Collocation
A combination of words that occur together more often than chance would predict and sound natural to native speakers, such as heavy rain, make a decision or deeply regret.
Phrasal Verb
A verb combined with one or two particles (adverbs or prepositions such as up, out, off or on) that together work as a single unit of meaning, often different from the verb alone, as in give up, look after or put up with.
Polysemy
The situation in which a single word has two or more related meanings, such as head (part of the body, leader of a group, front of a line) or run (move fast, manage, operate).
Register
The variety of language a speaker chooses for a particular situation, audience and purpose, especially its level of formality, as in kids (informal), children (neutral) and offspring (formal or technical).
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