10 Advanced C1 and C2 English Idioms

10 Advanced C1 and C2 English Idioms is a focused guide for high-level English learners who want to move from fluent to truly natural and sophisticated English. At the C1 and C2 levels, understanding advanced idioms is essential because native speakers often use them in professional discussions, debates, academic contexts, and media. These idioms are more nuanced and expressive than basic ones, and they often carry cultural or figurative meanings that are not easy to guess. This topic introduces 10 carefully selected advanced idioms commonly used by proficient speakers, helping learners sound more confident, polished, and native-like. Written in clear and learner-friendly English, this guide is ideal for advanced students, IELTS/CAE/CPE candidates, professionals, and serious English learners who want to elevate their vocabulary and communication skills.

Let’s have a look at the list.

C1 English Idioms:

1. Catch someone’s eye
2. Cut corners
3. Cry over spilled milk
4. Curiosity killed the cat
5. Close call

C2 English Idioms:

1. Curiosity killed the cat but satisfaction brought it back
2. Clean as a whistle
3. Cold feet
4. Cut the mustard
5. Caught red-handed

Now, let’s look at their meanings. 

C1 English Idioms:

• Catch someone’s eye – To attract someone’s attention.
• Cut corners – To do something in the easiest or cheapest way possible, often sacrificing quality.
• Cry over spilled milk – To be upset about something that has already happened and cannot be changed.
• Curiosity killed the cat – Being too curious can lead to trouble.
• Close call – A situation where something almost goes wrong but ends up being okay.

C2 English Idioms:

• Curiosity killed the cat, but satisfaction brought it back – Sometimes being curious can lead to trouble, but it can also lead to satisfying discoveries.
• Clean as a whistle – Very clean or tidy.
• Cold feet – To feel nervous or hesitant about doing something.
• Cut the mustard – To meet expectations or standards.
• Caught red-handed – To be caught in the act of doing something wrong or illegal.

Now, moving onto their usage with situations.

Catch someone’s eye

“Catch someone’s eye” is an idiom that means to attract someone’s attention.

Imagine you’re in a crowded room with lots of people talking and doing different things.

If you want to show someone something or talk to them, you might need to get their attention first. That’s where the idiom “catch someone’s eye” comes in.

When something catches your eye, it means it grabs your attention. It could be something colorful, like a bright balloon in the sky, or something interesting, like a funny picture.

For example, if you’re in class and you see a cool drawing your friend is working on, it might catch your eye and make you want to see it up close.

So, when we say, “catch someone’s eye,” we mean getting someone to notice something or someone by making it stand out or being interesting.

Cut corners

“Cut corners” is an idiom that means to do something in the easiest or quickest way, often by leaving out important steps or details. 

Imagine you have a big art project to do. You have to draw a picture, color it, and then cut it out neatly. But you’re running out of time, and you want to finish quickly.

Instead of doing all the steps carefully, you might decide to “cut corners” to finish faster. This means you might skip coloring neatly or not cut out the picture perfectly.

In everyday life, when we say someone is “cutting corners,” it means they are not doing something the right way.

They might be trying to save time or effort, but it can also mean they’re not doing their best work.

For example, if you’re cleaning your room and you quickly stuff things under your bed instead of putting them away properly, you’re cutting corners.

So, “cutting corners” means doing something quickly but not as well as you could if you took the time to do it properly.

It’s important to remember that sometimes it’s better to take your time and do things the right way, even if it takes a little longer.

Cry over spilled milk

Now, here’s where the idiom “Cry over spilled milk” comes in. When we say this phrase, it means being upset or worried about something that has already happened and can’t be changed.

Just like how crying won’t put the spilled milk back in the glass, being upset about something that’s already done won’t fix it.

So, “Cry over spilled milk” is a way of saying that it’s not helpful to keep worrying about things that are already done and can’t be undone.

It’s a reminder to focus on what we can do now, rather than getting stuck on things that are in the past.

Imagine there’s a cat named Whiskers.

Whiskers is a very curious cat, always poking its nose into everything to see what’s going on. One day, Whiskers sees a shiny object and can’t resist investigating.

But oh no! It turns out to be something dangerous, and Whiskers gets hurt. In this story, Whiskers’ curiosity led to trouble.

Now, people use the saying “Curiosity killed the cat” to remind us that being too curious or nosy can sometimes lead to problems.

It doesn’t mean that being curious is always bad, but it’s a cautionary saying to be careful and not get into risky situations just because we’re curious.

So, when you hear “Curiosity killed the cat,” it’s like a little warning to be curious in safe ways and not to get into things that might be dangerous or harmful.

It’s good to be curious, but it’s also important to be smart and cautious about it.

Imagine you’re playing outside with your friends, and suddenly, a ball comes flying towards you, but you manage to duck just in time, and the ball goes past you without hitting you.

Phew! That was a close call! It means something almost happened, but luckily, it didn’t.

In everyday life, a close call is when something dangerous or bad almost happens, but we manage to avoid it just in time.

For example, if you’re crossing the street and a car comes speeding by but stops just before hitting you, that’s a close call. Or if you’re about to trip on a toy but catch yourself before falling, that’s also a close call.

So, a close call is like a reminder that something scary or bad almost happened, but thankfully, everything turned out okay.

It’s a moment of relief after narrowly avoiding a potential problem.

So, when we say, “Curiosity killed the cat but satisfaction brought it back,” we mean that while being too curious can sometimes lead to problems or danger (like how Whiskers got into a little trouble), it can also lead to happy discoveries or experiences that make us feel good (like finding a new toy or a cozy spot).

It’s a way of saying that curiosity can have both good and bad outcomes, but overall, it’s a natural and important part of learning and exploring the world around us.

Clean as a whistle

Imagine you have a whistle, like the one a referee uses in sports.

When a whistle is clean, it means it doesn’t have any dirt or smudges on it. It’s shiny and looks new.

Now, when we say something is “clean as a whistle,” we’re not talking about an actual whistle.

Instead, we’re describing something that is very clean and tidy, just like a whistle that’s free from dirt and marks.

For example, if your room is very neat, with everything in its place, you can say it’s “clean as a whistle.”

Or if you wash your hands really well and they’re spotless, you can say they’re “clean as a whistle.”

So, “clean as a whistle” is a fun way to describe something that’s really clean and looks nice, just like a brand-new whistle without any dirt on it.

Imagine you’re about to do something exciting or maybe a little scary, like riding a big roller coaster for the first time.

You’re all set and excited, but just as you’re about to get on the ride, you start feeling nervous and unsure.

Your feet feel cold, and you might even start to think, “Do I really want to do this?”

When we say someone has “cold feet,” it means they’re feeling nervous or hesitant about doing something they were excited about or agreed to do.

It’s like when you’re all pumped up to jump into a swimming pool, but when you dip your toes in the water, it feels colder than you expected, and you hesitate.

For example, if you were going to perform in a school play but got scared at the last minute and didn’t want to go on stage, you could say you had “cold feet.”

Or if you planned to go on a hiking trip but felt unsure about it when the day came, that’s also having “cold feet.”

So, “cold feet” is a way of describing that feeling of nervousness or hesitation right before doing something, even if you were excited about it before.

It’s normal to have cold feet sometimes, and it can help us think carefully about our choices before we go ahead with them.

Imagine you have a sandwich, and you want to add mustard to make it taste better.

But if the mustard you use isn’t good or flavorful enough, it won’t make the sandwich taste as yummy as you hoped.

So, when we say something “cuts the mustard,” it means it meets expectations or does a good job at what it’s supposed to do, just like how good mustard makes a sandwich taste better.

For example, if you’re playing a game with your friends, and you do really well, you can say you “cut the mustard” because you met or exceeded everyone’s expectations.

Or if you’re baking cookies, and they turn out delicious, you can say your cookies “cut the mustard” because they’re just as good as you hoped they would be.

So, “cutting the mustard” is like saying something is good enough or meets the standard we expected. It’s a fun way of saying that something does what it’s supposed to do and does it well.