10 English Idioms About Age

For English learners, idioms can be a big challenge. They usually don’t have literal meanings and easily cause confusion out of context.

But they’re a very common part of speech, and learning them will help you understand native speakers. 

If you can get comfortable enough to use them in conversation, you can really impress your audience.

Idioms about age are a common theme, maybe because they make it easier to talk about a topic that can be uncomfortable for some.

In this post, you’ll learn 10 common English idioms about age and how to use them.


1. Coming of age

If someone has come of age, then they’ve reached adulthood or a certain level of maturity. This differs across cultures, and there are many ceremonies associated with this around the world. This idiom doesn’t necessarily refer to a specific age. Rather, it means the age that you’re considered to be responsible for yourself.

This idiom is also commonly used to refer to particular styles of films and books that follow the journey of a young child to adulthood. These are known as “coming-of-age stories.”

A: Hey, have you seen “Stand By Me?”

B: No, I haven’t.

A: It’s a classic coming-of-age movie. Let’s watch it this weekend.

2. I wasn’t born yesterday

This is a great idiom, as you may be able to understand the meaning already. When somebody says they weren’t born yesterday, they’re saying that they’re not easily fooled or deceived. It means that, because of their experience and age, they know better or don’t believe you.

A: Did you hear the bank is handing out free money?!

B: Don’t be so silly. I wasn’t born yesterday!

3. Age is just a number

This idiom is quite positive and uplifting (makes you feel good). It makes you think about how you perceive (see) life. When somebody says that age is just a number, they’re stating that our age shouldn’t define us as a person. In other words, no matter how old we are, we can do anything.

For example, Yuichiro Miuro climbed Mt. Everest when he was 80 years old. This shows that age is just a number.

4. Age before beauty

This humorous and common idiom is used mostly in social situations where the two people are familiar with each other. Essentially, it’s a way to jokingly suggest that the elder person should go before the younger person.

Perhaps you’re sitting down for a nice meal with your family. You could say:

Help yourself, first, Uncle. You know what they say: age before beauty!

5. Act your age

Act your age is an idiom that’s often used as a command or a suggestion (it’s often said with anger or frustration). It’s used to tell somebody to stop acting in an immature or childish way. The idiom is often used in reference to behavior. While not always, you may commonly hear it used towards a child who’s behaving poorly.

It can also be used to describe a situation in which somebody isn’t acting in a way that’s expected of their age group.

A: I’m a bit worried about my son, Thomas.

B: Why?

A: He’s always talking about mortgages and taxes. He’s only 12! Sometimes, I wish he’d just act his age and play soccer with his friends.

6. One foot in the grave

This is a bit of a darker idiom. To have one foot in the grave is to be very old and considered close to death. If you hear someone say this, they’re probably talking about someone who’s not present.

A grave is a hole that’s dug in the ground where you’re laid to rest after you’ve passed away. In this way, you can see the symbolism of the expression.

A: I saw Bill last night.

B: How is he?

A: He looks very old. I think he’s got one foot in the grave.

7. Ripe old age

This idiom is very similar to the previous one and refers to a person who has aged a lot. If someone lived to a ripe old age, they lived to old age with generally good health. “Ripe” refers to fruit and vegetables. When they’re ripe, they’re ready to be eaten and are at their best.

You’ll commonly hear this idiom used to talk about somebody who has passed away. In the video below, you’ll hear Christopher Walken use the idiom in a joking way. 

To use the idiom in the standard way (not as a joke) you might say something like:

My grandfather lived to the ripe old age of 89.

8. You can’t teach an old dog new tricks

This unique and flexible idiom refers to behavior. It’s included in our list of age idioms because it also relates to time.

You can’t teach an old dog new tricks refers to a situation in which it’s challenging to teach somebody something new. This is especially true if they’ve been doing something a certain way for a long time.

A: I’m trying to teach my dad how to use Instagram.

B: How’s it going?

A: It’s very difficult. You know, you can’t teach an old dog new tricks.

9. A spring chicken

Simply, a spring chicken is an idiom for a young person. It’s usually used by older people to refer to a younger individual.

You may also hear it used as self-deprecating humor (when you put yourself down or insult yourself). It’s common for an older individual to reference their age by saying something like:

I’m no spring chicken!

10. Knee-high to a grasshopper

Similar to the last idiom, knee-high to a grasshopper also refers to a young person. If someone is knee-high to a grasshopper, then they’re very young or small. Commonly, this idiom is used to refer to a small child.

You’ll find that this idiom is also used to talk about somebody in the past. For example, you might hear somebody say:

I remember you when you were knee-high to a grasshopper.

They could also say:

I’ve known you since you were knee-high to a grasshopper.

It’s a fun and very common way to refer to somebody’s young age or stature or reference a relationship with them when they were young.

How to Use Idioms About Age 

Age can be a sensitive topic in English. This means that not everybody likes to discuss it openly. 

It’s all about understanding the meaning behind the idiom and using your best judgment to decide when to use it. It’s equally important to consider your relationship with the individual with whom you’re speaking.

For example, I may use an idiom such as “you’re getting on a bit” (you’re physically aging) to describe an older friend, and we would both consider it a humorous joke. However, if said to a stranger on the street, it could be considered an insult or personal attack.

Since using idioms requires some subtlety (especially age idioms), it’s best to learn them in context. You can do this easily by listening to real conversations between native English speakers with a language program like FluentU.

FluentU takes authentic videos—like music videos, movie trailers, news and inspiring talks—and turns them into personalized language learning lessons.

You can try FluentU for free for 2 weeks. Check out the website or download the iOS app or Android app.

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As you keep paying attention to idioms in media and real-life conversations, you’ll build up a solid familiarity with them.

With dedication and practice, you’ll soon be using them like a native! 

And One More Thing...

If you like learning English through movies and online media, you should also check out FluentU. FluentU lets you learn English from popular talk shows, catchy music videos and funny commercials, as you can see here:


If you want to watch it, the FluentU app has probably got it.

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For example, when you tap on the word "searching," you see this:


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Start using the FluentU website on your computer or tablet or, better yet, download the FluentU app from the iTunes or Google Play store. Click here to take advantage of our current sale! (Expires at the end of this month.)

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