Here are some idiomatic expressions formed around words beginning with letter C.
Castles in the air
Dreams or plans that will never be achieved
The cat’s whiskers
This is an informal expression used to refer to an excellent person or thing.
Let the cat out of the bag
To let the cat out of the bag is to reveal a secret by mistake.
Put / set the cat among the pigeons
To set the cat among the pigeons is to do something that will most probably cause trouble.
Stand on ceremony
To stand on ceremony is to insist on formal behavior.
Separate the wheat from the chaff
To separate the wheat from the chaff is to pick out what is valuable from what is worthless.
Cheer someone up
To cheer someone up is to make them less miserable.
A chequered career
To have a chequered career is to have successful and unsuccessful periods in one’s career.
Keep your chin up
To keep your chin up is to remain cheerful in difficult circumstances.
Take it on the chin
To take it on the chin is to accept a difficult situation without complaining.
A chip off the old block
This is an informal expression used to refer to someone who resembles their father or mother in character.
When the chips are down
This is an informal expression used to mean that a very serious situation has arisen.
Chuck something away
To chuck something away is to throw something away.
Churn something out
To churn something out is to produce something in large quantities without worrying too much about their quality.
Come full circle
When something comes to a full circle, they return to a previous position.
Clean someone out
To clean someone out is to take all someone’s money.
To clean up is to make a large profit.
Come clean / make a clean breast of it
To make a clean breast of it is to fully confess something.
Clear the air
To clear the air is to improve a tense situation by frank discussion.
In the clear
When someone is in the clear, they are no longer under suspicion or in danger.
At close quarters
This expression is used to refer to a contest won or lost by a very small margin.
Close shave / close call
An expression used to refer to a narrow escape from danger or disaster.
Behind closed doors
If something happens behind closed doors, it happens in private.
In the closet
When someone is in the closet, they are not open about being homosexual. And when someone is out of the closet, they are open about being homosexual.
Have your heads in the clouds
When you have your heads in the clouds, you are full of unrealistic ideas.
On cloud nine
When you are on cloud nine, you are very happy.
Under a cloud
When you are under a cloud, you are under suspicion of having done something wrong.
Haul someone over the coals
To haul someone over the coals is to reprimand them severely.
The coast is clear
When the coast is clear, there is no danger of being caught or seen.
On someone’s coat-tails
When you are on someone’s coat-tails, you benefit from another person’s success.
Warm the cockles of someone’s heart
To warm the cockles of someone’s heart is to give them a feeling of contentment or happiness.
Get cold feet
When you get cold feet, you lose your nerve.
Give someone the cold shoulder
To give someone the cold shoulder is to treat them with deliberate unfriendliness.
In cold blood
When someone is killed in cold blood, they are killed in deliberately cruel ways.
To collect yourself is to regain your self control.
Keep someone company
To keep someone company is to spend time with them so that they wouldn’t feel lonely or bored.
Conduct yourself well
To conduct yourself well is to behave well.
When you are in contention, you have a good chance of success in a contest.
Out of contention
When you are out of contention, you have little chance of success in a contest.
Keep your cool
To keep your cool is to stay calm and controlled. To lose your cool is to become angry and agitated.
Have the courage of your convictions
To have the courage of your convictions is to act on your beliefs in spite of disapproval or danger.
Crack down on something
To crack down on something is to take strong action against it.
At cross purposes
When two people are at cross purposes, they misunderstand each other.
Cross something off
To cross something off is to delete an item from a list.
To cross swords is to have an argument or dispute.
Take up the cudgels
To take up the cudgels is to defend someone or something strongly.
If something happens on cue, it happens at the right moment.
Not someone’s cup of tea
If something is not your cup of tea, it is not what you like or enjoy.
It is curtains
When it is curtains for something, it reaches a disastrous end.
Be cut out for
When you are cut out for something, you have the exact qualities required for a role.
A cut above
When you are a cut above, you are better than others.
Cut and dried
If something is cut and dried, it is decided in advance.
Cut and run
To cut and run is to make a quick departure from a difficult or dangerous situation.
Cut both ways
If a point cuts both ways, it serves both sides of an argument or it has both good and bad effects.
To cut corners is to compromise on quality with the objective of saving time or money.
Cut a dash
If something cuts a dash, it is stylish or impressive.
Cut someone dead
To cut someone dead is to ignore them completely.
To cut in is to interrupt someone.
Cut the mustard
To cut the mustard is to reach the required standard.
Cut no ice
If something cuts no ice, it has no effect or influence.
Cut someone out
To cut someone out is to exclude them.
Cut up rough
To cut up rough is to behave in an aggressive or awkward way.