What is an idiom?

An idiom is an expression, utterance, word or phrase that has a figurative meaning, and it has the following characteristics:

1. It is fixed and is recognised by native speakers. You cannot make up your own!

2. It uses language in a non-literal – metaphorical – way.

The following are examples:

1. Tin up to my eyes in work at the moment.   

2. At the meeting I felt a bit out of my depth.

3. I was over the moon when I heard she’d had twins!   

4. It broke my mother’s heart to see her home burn to the ground. 

If you are up to your eyes, you are very busy. If you are out of your depth, you might be in the sea, but you are more likely to be in a situation which you do not understand for some reason. If you are over the moon, you are extremely happy about something. If something breaks your heart, you are very sad about it.

In these examples it is obvious that the idiom is an entier expression. This is the traditional view of idioms. But there is a lot more language which is idiomatic. For example, there are lots of individual words with idiomatic uses :

Literal Use

1. The river flooded several villages.
2. Piles of rubbish lay everywhere.
3. I love roast potatoes.
4. I’ve got an uncle at sea.

Idiomatic Use

1. The crowd flooded on to the pitch.
2. He’s got piles of money.
3. Euthanasia. Now, that’s a very hot potato!
4. I’m all at sea.

Why idioms are important?

1. Words don’t come singly

You have probably devoted a long time learning new words. Words, however, do not just come individually, they also come in expressions – in groups. Idioms are among the most common of these expressions. There are thousands of them in English:

1. I could eat a horse. 

2. Money doesn’t grow on trees. It’s not up to scratch. 

3. I got there in the nick of time.

2. Language is literal and metaphorical

Sometimes when we use language we use it in a very literal way:

I’ve been outfishing, but caught absolutely nothing!

The same language can be used in a non-literal way – a metaphorical way:

Yesterday I caught the bus. 

My car wouldn’t start.

Here are more examples of this metaphorical use of catch:

He caught my attention. 

Wait while I catch my breath! 

Look at that tan! You’ve caught the sun! 

I didn’t quite catch what you said.

The metaphorical uses of a word are often more common than the literal ones.

3. Idioms have grammar

Some idiomatic expressions are fixed and cannot change:

Two heads are better than one.

Very often you can change the tense and the pronoun:

I’m/She’s/We were all at sixes and sevens.

What is a metaphor?

Metaphors exist in all languages. You use them in your own language. A metaphor uses one idea to stand for another idea. Above, we saw the simple idea: A crowd is water. When you have that idea in your mind, the crowd can flow, flood, or trickle. Here are some of the common metaphors:

1. Time is money.
We save time. We can spare 5 minutes. We can run out of time.

2. Business is war.
Advertising is a minefield in which you have targets and keep your sights on what your competitors are doing.

3. Life is a journey.
You can be on the road to recovery. You might be at a crossroads in your life because you are in a dead-end job.

Why are idioms and metaphors so important?

First of all, idioms are important because they are very common. It is almost impossible to speak, read, or listen to English without meeting idiomatic language. This is not something you can leave until you reach an advanced level. All native speaker English is idiomatic. Every newspaper is full of metaphorical language. You cannot avoid it or leave it till later.

The second reason is that very often the metaphorical use of a word is more common today than its literal use. For example, we know that farmers plough their fields, but you can say:

plough through a long novel or report; 

you can plough on with your work; 

you can plough money into a business; 

profits can be ploughed back into a company; 

a lorry can plough into a row of parked cars. 

Using plough in its literal farming meaning is now much rarer than all its other non-literal uses. But it is important for you to know the literal meaning. Often the literal meaning creates a picture in your mind and this picture makes the other meanings easier to understand.

The third reason that this kind of language is important is because it is fun to learn and to use. Because there is so much to learn, anything which helps you to remember things is important and if the language you are learning is more colourful and interesting, there is more chance that you will remember it. You will also sound more natural if your English contains more idioms.