English Idioms: Meanings, and Origins That Are Often Uncertain

An idiom is a phrase whose meaning isn't clear from its words. Native speakers use them constantly, and learners find them baffling. Their origins are fascinating, but often less certain than the popular stories suggest.

Meanings first

• Break the ice: to ease initial awkwardness.
• Bite the bullet: to face something unpleasant.
• Hit the nail on the head: to be exactly right.
• Once in a blue moon: very rarely.
• Under the weather: feeling unwell.
• Spill the beans: to reveal a secret.
• The ball is in your court: it's your turn to act.
• Cost an arm and a leg: to be very expensive.
• A piece of cake: very easy.
• Let the cat out of the bag: to reveal a secret by accident.

Origins with reasonable support

• Learn the ropes: likely from sailing, where new sailors had to learn the many ropes of a ship's rigging.
• By and large: thought to come from sailing, where ships sailed by the wind or large, with the wind behind them. It came to mean "generally".
• Show your true colours: from ships displaying their flags, sometimes falsely, to deceive enemies.
• Barking up the wrong tree: from hunting dogs that chase prey up a tree, and can be wrong about which tree it's in.
• Pass the buck: from poker, where a marker called a "buck" showed whose turn it was to deal.
• Rule of thumb: a rough guide based on practical experience, from the use of a thumb to measure.

Popular stories that deserve caution

Many origin stories circulate online with great confidence, but etymologists often find little evidence for them.

• Raining cats and dogs: there are many theories, but no widely accepted explanation.
• Saved by the bell: stories about coffins and bells are usually dismissed by dictionaries. A boxing origin is more plausible, but not certain.
• The whole nine yards: its origin is unknown, despite many explanations.
• Let the cat out of the bag: a story about a market trader swapping a cat for a piglet is popular, but not proven.
• Under the weather: often said to be nautical, but the evidence is unclear.
• Rule of thumb as a legal rule about beating wives: this is a persistent myth without supporting evidence.

A good rule: if an origin story is neat, vivid and unsourced, be sceptical.

How dictionaries handle it

Reliable dictionaries give the earliest known use, and label origins "unknown" or "uncertain" when that's the case. That's a sign of quality, not a failing.

Learning idioms

1. Learn them in whole phrases. Changing a word usually breaks the idiom.
2. Use them in context, with example sentences.
3. Notice register. Some are casual, some formal, some old-fashioned.
4. Don't over-use. A well-placed idiom is effective; a string of them sounds forced.
5. Watch for cultural differences. Idioms vary between British, American and other Englishes.

Literal versus figurative

Idioms can be misread if taken literally. It's raining cats and dogs is a common example, and a fun way to remind yourself that English is full of figurative surprises.

Practice

Choose five idioms, write their meanings, and use each in a sentence. Then check them in a dictionary for labelling and any notes on origin.

Look up idioms and phrases with English Dictionary →