What Is an Idiom? Definition, Examples, and British Favourites

You’ve said “break the ice” or “spill the beans” without thinking twice — those odd little phrases that make perfect sense to a native speaker and absolutely none to someone learning English. That’s the magic of idioms: they carry meaning that isn’t written in the words themselves.

Estimated number of English idioms: 25,000 · Idioms used by average speaker per day: ~20 · Oldest recorded idiom (approx.): to kick the bucket (1785)

Quick snapshot

1Confirmed facts

An idiom’s meaning can’t be guessed from its individual words (Cambridge English Dictionary (learner dictionary))
Idioms are a type of figurative language used in daily speech and literature (Doodle Learning (UK learning platform))

2What’s unclear

The exact number of English idioms — 25,000 is an estimate, not a census (British Council TeachingEnglish (global English teaching body))
The origins of many idioms are debated or lost (British Council TeachingEnglish (global English teaching body))

3Timeline signal

4What’s next

Read on for 10 common idioms with meanings and real example sentences
You’ll also find kid-friendly explanations and the British phrases locals actually use

Nine facts, one pattern: the more idiomatic a phrase is, the less its literal words help you.

Fact	Detail
Formal definition	A group of words whose meaning is different from the meanings of the individual words (Oxford Learner’s Dictionaries (dictionary for English learners))
British dictionary view	Words take a different meaning together from the meaning each word would have separately (Collins English Dictionary (UK dictionary publisher))
Learner-friendly definition	A group of words used together with a meaning you cannot guess from the separate words (Cambridge Learner’s Dictionary (learner dictionary))
Type of language	According to Doodle Learning (UK learning platform), idioms are a type of figurative language used in daily speech and literature
Estimated total in English	Around 25,000 (widely cited estimate)
Idioms traced to Shakespeare	More than 100
Earliest recorded example	“Kick the bucket”, found in print from 1785
Everyday use	Idioms are part of everyday British conversation (EF United Kingdom (UK English teaching organisation))
Origins over time	Idioms’ origins and meanings can be explored through how English changes over time (British Council TeachingEnglish (global English teaching body))

Editor’s note: The 25,000 figure and the 1785 date are estimates from the research literature. There is no single official register of English idioms, so counts and first-recorded dates vary by source.

What is the real meaning of idiom?

Open any serious English dictionary and you’ll meet the same core idea: an idiom is a group of words whose meaning as a whole is different from the meaning of each word on its own. Oxford Learner’s Dictionaries (dictionary for English learners) defines it as a group of words whose meaning is different from the meanings of the individual words, and Collins English Dictionary (UK dictionary publisher) makes the same point from a slightly different angle: the words have a different meaning when used together from the meaning each word would have separately. In plain English, an idiom is a phrase that means what it means, not what its words say.

Why this matters

Idioms aren’t decorative extras — they’re how English speakers actually talk. Skip them and you understand the grammar perfectly but miss half the message.

What is an idiom in English?

An idiom is a fixed expression — you can’t swap words in or out without breaking it.
Idioms are a form of figurative language, so they sit alongside metaphors and similes.
They belong to everyday conversation, and British English teaching materials treat them as standard communication rather than literary flourishes.

A quick test: translate an English idiom word-for-word into another language and it usually stops making sense. That’s because an idiom carries its meaning as a single block, not as a sum of its parts. “Under the weather” has nothing to do with weather, and “biting the bullet” involves no bullet — the image in the phrase is a clue, not the answer.

What is an idiom vs metaphor?

An idiom is a fixed phrase: “spill the beans” can’t become “spill the peas”.
A metaphor is a comparison: “time is a thief” can be reworded as “time steals our years” and still makes sense.
Idioms often start life as metaphors — the comparison gets repeated until it hardens into a set phrase.

That hardening is the difference. Metaphors stay flexible because the speaker is actively comparing two things. Idioms are the finished product: the comparison has been used so often that the phrase now travels as one unit. When an English speaker says “the ball is in your court”, nobody pictures a tennis match — they just know it means it’s your turn to act.

Bottom line: The trade-off: idioms make English vivid and compact for insiders, and genuinely disorienting for outsiders. Learning them is less about memorising words and more about absorbing the culture that produced them.

What are 10 examples of idioms and their meanings?

Here are ten idioms worth knowing. The first six come from UK teaching resources; the last four are so common that you’ll hear them everywhere in casual speech.

What is an example of an idiom?

Break the ice — to start a conversation in a social setting.
Under the weather — feeling ill or unwell.
Bite the bullet — to do something difficult or unpleasant that you’ve been avoiding.

Ten idioms, one pattern: the real meaning never matches the literal words. The source for each meaning sits in the second column.

Idiom	Meaning	Example sentence
Break the ice	To start a conversation in a social setting (Twinkl UK (teaching resources site))	“She told a joke to break the ice at the meeting.”
Under the weather	Feeling ill or unwell (Twinkl UK)	“I’m a bit under the weather, so I’ll skip the gym.”
Bite the bullet	To do something difficult or unpleasant you’ve been avoiding (Twinkl UK)	“He finally bit the bullet and booked the dentist.”
A penny for your thoughts	Asking someone what they’re thinking (Oxbridge GCSE Tutor (UK tutoring service))	“You look deep in thought — a penny for your thoughts?”
At the drop of a hat	Doing something immediately, without waiting (Oxbridge GCSE Tutor)	“She’d move to the coast at the drop of a hat.”
Actions speak louder than words	What you do matters more than what you say (Oxbridge GCSE Tutor)	“He apologised, but actions speak louder than words.”
Spill the beans	To reveal a secret	“Don’t spill the beans about the surprise.”
Piece of cake	Something very easy	“The quiz was a piece of cake.”
Hit the sack	To go to bed	“I’m exhausted — time to hit the sack.”
Burn the midnight oil	To work late into the night	“She burned the midnight oil before the exam.”

According to Oxbridge GCSE Tutor, “a penny for your thoughts”, “at the drop of a hat”, and “actions speak louder than words” are standard items on UK idiom lists — the kind of phrase that turns up in conversation long before it appears in a textbook. The example sentences above show each idiom doing its job in context, which is exactly how native speakers learn them in the first place.

What is a good idiom sentence?

“A penny for your thoughts?” — a gentle way to ask what someone is thinking.
“Let’s break the ice with a quick game.” — a natural opener for a meeting.
“I’ve been under the weather all week.” — casual and completely normal in British speech.

Notice what these sentences share: the idiom isn’t translated or explained — it’s just used. A good example sentence shows the phrase doing its job in context, and that context is what pins the meaning in a learner’s memory.

Bottom line: What this means: the fastest way to learn idioms is to meet them in real sentences, not list them in a notebook. Each phrase behaves like a small character — once you see it in action, you start recognising it everywhere.

How do you explain idioms to a child?

The trick is to make the literal image funny. Children don’t need a grammar lecture — they need to see that “it’s raining cats and dogs” is a ridiculous picture, and that the phrase really means heavy rain. Doodle Learning (UK learning platform) describes idioms as a type