A cat burglar is a skillful thief who breaks into places without disturbing people or setting off alarms.
(USA) When I used to ask my grandma what was for dinner, she would say 'cat fur and kitty britches'. This was her Ozark way of telling me that I would get what she cooked. (Ozark is a region in the center of the United States)
If someone asks if the cat has got your tongue, they want to know why you are not speaking when they think you should.
If you have a short sleep during the day, you are cat napping.
(Scot) A cat's lick is a very quick wash.
(USA) Something that is the cat's pajamas is excellent.
Something excellent is the cat's whiskers.
This means that people should try to get something any way they can.
If you catch hell, you get into trouble or get scolded. ('Catch heck' is also used.)
If you catch some z's, you get some sleep.
If someone is caught red-handed, they are found doing something wrong or illegal.
Catch-22 is a situation where conflicting rules make the desired outcome impossible. It comes from a novel by the American author Joseph Heller, in which pilots would not have to fly missions if they were mentally ill, but not wanting to fly dangerous missions was held to be proof of sanity, so they had to fly anyway. ('Catch 22', without the hyphen, is also used.)
Caught with your hand in the cookie jar
Things, or people, that are like chalk and cheese are very different and have nothing in common.
If someone is champing at the bit, they are very eager to accomplish something. ('Chomping at the bit' is also used.)
Champagne taste on a beer budget
Someone who lives above their means and likes things they cannot afford has champagne taste on a beer budget.
To betray impatience, as to begin some action. "I'm champing at the bit to tell you" "Chomping at the bit" is also commonly used, though some regard it as an error.
If people change horses in midstream, they change plans or leaders when they are in the middle of something, even though it may be very risky to do so.
If you change the way you think or feel about something, you have a change of heart.
If you change tack, you use a different method for dealing with something.
If someone changes their ideas or the way they talk about them, they change their tune.
When something/someone really annoys you, it chaps your ass.
When you know something very well, and can quote it, you know it chapter and verse.
This idiom means that family members are more important than anyone else, and should be the focus of a person's efforts.
If someone chases rainbows, they try to do something that they will never achieve.
If you are chasing your tail, you are very busy but not being very productive.
(UK) If something is very inexpensive, it is as cheap as chips.
If something's cheap at half the price, it's very cheap indeed.
A cheap shot is an unprincipled criticism.
If someone cheats death, they narrowly avoid a major problem or accident.
If things or people are cheek by jowl, they are very close together.
If people cherry pick, they choose things that support their position, while ignoring things that contradict it.
If someone is chewing on a bone, he or she is thinking about something intently.
If you chew the cud, you think carefully about something.
If you chew the fat with someone, you talk at leisure with them.
If something is small or unimportant, especially money, it is chickenfeed.
If something is child's play, it is very easy and simple.
Chinese walls are regulatory information barriers that aim to stop the flow of information that could be misused, especially in financial corporations.
(UK) When a story is told from person to person, especially if it is gossip or scandal, it inevitably gets distorted and exaggerated. This process is called Chinese whispers.
If someone is a chip off the old block, they closely resemble one or both of the parents in character.
If someone has a chip on their shoulder, they are resentful about something and feel that they have been treated badly.
If things chop and change, they keep changing, often unexpectedly.
If you cannot get or put a cigarette paper between people, they are so closely bonded that nothing will separate them or their positions on issues.
If someone is circling the drain, they are spiraling downward to a usually inevitable death.
(USA) If you circle the wagons, you stop communicating with people who don't think the same way as you to avoid their ideas. It can also mean to bring everyone together to defend a group against an attack.
If someone is circling the drain, they are very near death and have little time to live. The phrase can also describe a project or plan or campaign that that is on the brink of failure.
Someone who's a class act is exceptional in what they do.
If something is as clean as a whistle, it is extremely clean, spotless. It can also be used to mean 'completely', though this meaning is less common nowadays. If somebody is clean as a whistle, they are not involved in anything illegal.
If something or someone has a clean bill of health, then there's nothing wrong; everything's fine.
If you make a clean break, you break away completely from something.
Someone with clean hands, or who keeps their hands clean, is not involved in illegal or immoral activities.
When someone has a clean sheet, they have got no criminal record or problems affecting their reputation. In football and other sports, a goalkeeper has a clean sheet when let no goals in.