English idioms are a group of words which have a meaning which isn’t obvious from looking at the individual words (learn more here). They are used so often in everyday English, if you don’t know them, it’s almost impossible to understand the context. Learning idioms will improve your understanding of the English language and enrich your English vocabulary.

Here are 10 common English idioms for you:

1 A piece of cake

Meaning: something that easy to do


I finished my exam 30 minutes early. It was a piece of cake because it was incredibly

2 Cost an arm and a leg

Meaning: very expensive


A college education in America costs an arm and a leg.

3 Break a leg

Meaning: used for wishing someone good luck, especially before a performance


“Break a leg!” shouted the stage director to his actors before the beginning of the play.

4 Hits the books

Meaning: to study


I can’t go out tonight. I need to hit the books.

5 Let the cat out of the bag

Meaning: to reveal a secret, usually by mistake

Example: I was trying to keep the party a secret, but Mel went and let the cat out of the bag.

6 Hit the nail on the head

Meaning: to describe exactly what is causing a situation or problem


A: Did you hear about Wendy and John?

B: Let me guess, they are getting a divorce

A: Wow, you hit the nail on the head. How did you know?

7 Pig might fly

Meaning: said when you think that there is no chance at all something happening

Example: “ I’ll have finished it by tomorrow.” “And pigs might fly!”

8 You can’t judge a book by its over

Meaning: said to show that you cannot know what something or someone is like by looking only at that person or thing’s appearance


That man may look very small and insignificant, but don’t judge a book by its cover– he’s a very powerful man in his circle.

9 Bite off more than you can chew

Meaning: to try to do something that is too difficult for you


By accepting two part-time jobs, he is clearly biting off more than he can chew.

10 Scratch someone’s back

Meaning: to offer to help someone if they help you


A: Would you please give me a hand with my math homework?

B: I’ll do it if you promise to help me with the housework later. Scratch my back and I’ll scratch yours.

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