List of U Idioms:

A decorative logo with the words "U" idioms: definitions and examples

These U idioms are the most commonly used idioms beginning with the letter "U" of course. That is, the main word in the idiom starts with a "U"). If you want to learn idioms beginning with other letters, click here to go to the main idioms page

Before we get started, in case you forgot, an idiom is a group of words whose meaning is different from the individual words if you looked them up separately in the dictionary.

I always recommend that my students concentrate on understanding idioms rather than trying to use  them in their own speech at the beginning.

However, to become fluent in the language, eventually you will also want to be able to use them. You can practice by writing a sentence (or two!) in the comments because I am here to help correct any mistakes you might make. Okay? So... here's the list!

U Idioms


unaccustomed to someone/something:  not used to something.

  • I moved here three years ago and I’m still unaccustomed to this cold weather.
  • I’m unaccustomed to hearing women using bad language.


under arrest:  when the police take someone into custody (arrests them) and takes them to the police station.

  • The police chased the criminals for five blocks before they captured them and placed them under arrest.
  • The trial will be difficult because the policeman did not advise the defendant of his Miranda rights after he put him under arrest.

under certain circumstances:  in certain situations.

  • Under certain circumstances you can attend the training for free.
  • It’s possible to see the mountains from here under certain circumstances.

under scrutiny:  being closely watched, examined or investigated.

  • After I was caught smoking, my parents of put me under a lot more scrutiny.
  • The police had three people under close scrutiny for the theft of the art gallery’s paintings.

under construction being built.

  • This website is still under construction.
  • There’s a lot of traffic on the freeway because the bridge is under construction.

under cover:  hidden and being done secretly (especially used with police and law enforcement).

  • See that woman who looks like a prostitute? She’s really a police officer working under cover.
  • Many security guards at the shopping mall work under cover.

under fire:  being attacked by firearms or words.

  • When I met my boyfriend’s parents they had me under fire the entire evening.
  • The robbers were under fire for 20 minutes before they put down their weapons and surrendered to the police.

under oath:  having made a formal promise or taken an oath to say the truth.

  • The judge reminded the witness that he was under oath and should tell the truth.
  • You will go to jail if you lie under oath.

under one’s belt having the experience of doing something.

  • I felt a lot more confident after I got a year of teaching under my belt.
  • All applicants must have a college degree and at least one year of work experience under their belts to apply for this position.

under one’s breath:  speaking very quietly with a whisper (low voice).

  • Whenever I asked my kids to do their chores they complain under their breath.
  • This morning my father was grateful when I reminded him under my breath that it was my mother's birthday.

under one’s nose:  something easily seen or found.

  • She was looking for the perfect husband for several years when she realized her dream man—her next door neighbor—was under her nose the whole time.
  • I can’t find my sunglasses! They’re right under your nose;well actually, on top of your head!

under pressure:  experiencing a lot of stress and anxiety.

  • Our manager is under a lot of pressure since the new director doubled our sales target.
  • Most high school seniors are under pressure because they have to do well in school to get into a good college.

under the circumstances:  because of a certain condition, situation or circumstance.

  • I heard your husband’s brother recently died and I’m sure that must be difficult. Yes, it is but under the circumstances he’s actually doing very well.
  • Usually, you need an appointment to see the doctor but under the circumstances, he's agreed to see you before your flight leaves today. 

under the influence (of someone or something):  experiencing the effects of drugs, alcohol or the control of a powerful person.

  • Too many young pop singers and actors are arrested for driving under the influence these days.
  • It’s important to monitor who your children’s friends are so that they don’t become under the influence of bad kids.

under the table:  in secret (often doing something illegal).

  • Unfortunately, politicians sometimes award contracts to companies under the table.
  • When we got to the restaurant there was a long line, so I slipped a $20 bill to the hostess under the table and we were seated at a table 10 minutes later.

under the weather:  feeling sick, especially sick with the flu or a common cold.

  • I called in sick to work today because I was feeling under the weather.
  • No, it’s nothing serious I just feel under the weather today.


until all hours:  until very late.

  • We were up until all hours last night finishing the report before the deadline.
  • Our neighbors are so annoying, they play music really loud until all hours during the week.

until hell freezes over:  forever.

  • Those two will hate each other until hell freezes over.
  • I’m sure politicians will be liars until hell freezes over.

until someone is blue in the face:  talking for a very long time.

  • I explained how to operate the machine until I was blue in the face.
  • I yelled at my son for not coming home last night until I was blue in the face.


in unison:  together at the same time.

  • The children’s choir wasn’t very good today—they were hardly in unison.
  • When I asked my kids if they wanted to go to the zoo, they screamed “yes” in unison.


do the unthinkable:  to do something that’s not expected.

  • When I woke up this morning I discovered my husband had done the unthinkable; the dishes were washed, the floor had been cleaned and the children’s lunches were packed.
  • When people are very drunk they sometimes do the unthinkable.


not up to something:  don’t feel like doing something.

  • If you’re not up to going out tonight, let’s order a pizza and watch TV.
  • I’m not up to exercising today but I’m definitely going tomorrow no matter what.

right up there with someone/something:  is good / bad as someone/something else.

  • To me, doing homework is right up there with having a tooth pulled by the dentist.
  • Did you see her new ranking? She’s right up there with the top tennis players now.

up against someone/something:  in opposition with someone / something.

  • In her next match, she’s up against a much more difficult player.
  • I can’t go out tonight because I’m up against a tough deadline and have to work.

up and around/about:  out of bed after illness and moving again.

  • After the surgery, she was up and about after just a week.
  • It’s so nice to be up and around after being in bed with the flu for a week.

up and coming:  newly starting to be popular or successful.

  • Listen to this up-and-coming singer, she’s fantastic.
  • I read Sandy's blog because she really knows all the  fashion designers who are up and coming.

up and running:  functioning, working properly.

  • Luckily, the technician got the Internet up and running again after 20 minutes.
  • She had hoped to have the new department up and running by the new year, but everything was behind schedule.

up for something:  enthusiastic or interested about something.

  • Are you up for going skiing this weekend?
  • If anyone’s up for a movie tonight, I’m going to see the latest installment of the Spider-Man series.

up for grabs:  possible for anyone to have.

  • The director just announced this month’s contest and a new MacBook is up for grabs.
  • There are some gently-used ski jackets up for grabs in the staff lounge if anyone is interested.

up front:  clear and honest about something.

  • I wish you had been up front about how big your house was because I won’t be able to finish the painting job by the date you wanted.
  • I want to be up front about the amount of travel involved in this job:  you’ll be expected to travel at least one week every month.

up in arms upset, angry.

  • The entire team was up in arms when the coach said they would have to practice an extra 30 minutes each day.
  • I’m up in arms about the new fees my bank is going to start charging.

up in the air:  not decided about something, unsettled.

  • Our plans for the New Year’s are still up in the air but I’ll let you know what we decide in case you want to join us.
  • The person will select to replace the cleaner is still up in the air but we have a good list of candidates to choose from.

up in years:  old, elderly.

  • She’s up in years now but everyone thinks she’s 20 years younger than she is.
  • When I get up in years I want to move somewhere where there’s a warm climate.

up one’s alley:  an activity someone likes and is good at.

  • I hate fixing things but luckily home repair is up my wife’s alley.
  • Cooking is up her alley so she decided to quit her job and open a catering business.

up the creek:  in trouble or a difficult situation.

  • I’m up the creek!  My credit card bill is due in two days but I don’t get paid until next week.
  • We missed our flight and now were up the creek because there are no available seats on any flights until next Tuesday.

up to someone:  to be responsible for doing something.

  • It's not important what I think; the decision is up to my boss.
  • If you want to lose weight, it’s up to you to eat better and start exercising.

up to something:  secretly doing or planning something.

  • Whenever it’s quiet at home I know my kids are up to something.
  • When no one wished me a happy birthday all morning I knew my team was up to something.

up-to-date:  to the latest standards.

  • These figures don’t look right. Can you make sure they are up-to-date?
  • It’s important to keep your software up-to-date so that you are protected against new viruses.

up to it:  having the desire, interest or capability to do something.

  • I really should do some financial planning but I’m not up to it.
  • I just asked Suzanne to come with us to the shopping mall but she’s not up to it.

up to no good:  doing something wrong or bad.

  • My puppy is always up to no good so I have to watch her very carefully.
  • My husband has been coming home very late and I’m worried he’s up to no good.

up to one’s eyeballs:  a lot of something undesirable.

  • During tax season, accountants are up to their eyeballs with work.
  • I’m up to my eyeballs in debt and need to stop using my credit cards.

up-to-the-minute:  the most recent or latest.

  • At Channel 5 news, we deliver up-to-the-minute reports about traffic, weather and news that’s important to you.
  • Check the leader board for up-to-the-minute results in the tournament.

up until:  until, to a certain time.

  • I was up until 2 AM finishing my homework last night so I'm exhausted.
  • Up until we got married my husband was a super loving guy.


have the upper hand:  having power, control or advantage.

  • Children who come from wealthy families have the upper hand when applying to college.
  • My dogs are always fighting but this one has the upper hand because he’s stronger and faster.


ups and downs:  good and bad things;  both good and bad times.

  • Even the best marriages have their ups and downs.
  • I really liked his talk because he discussed both the ups and downs of being a famous actor.


upside down:  with the top side facing downward;  changing something completely.

  • Her life turned upside down after having twins.
  • If you hang those roses upside down, they’ll dry out in a perfect bouquet.


be uptight:  worried and anxious.

  • My last girlfriend was gorgeous but she was so uptight,  while my current girlfriend is very average looking but completely confident about her looks.
  • My mother is very uptight  about my grades at school.


use every trick in the book:  try everything or every possible method.

  • The match was so difficult she had to use every trick in the book to beat her opponent.
  • I’m not going to stop until I’ve used every trick in the book.

it’s no use/there’s no use:  there’s no reason to do or try something.

  • I’ve tried to talk to her but it’s no use—she’s inconsolable that he broke up with her.
  • There’s no use begging me to help because registration ended yesterday and the class is already full.

use up:  to finish all of something until nothing remains.

  • Help! Someone used up all the toilet paper and didn’t replace the roll with a new one.
  • I'm exhausted; I used up all my energy mowing the lawn this afternoon.


used to (do something):  had the habit of doing something in the past.

  • I used to hate spinach, but now it’s one of my favorite vegetables.
  • When I was a kid I used to live in Nigeria for five years because my father worked for an oil company.

used to (doing) something:  familiar with something;  accustomed to something.

  • I know you’re used to eating sugary foods but you’re going to have to change your diet if you want to get well.
  • Once you get used to using this software, you’re going to love it.


as usual:  as expected, as normally happens.

  • If he’s late as usual,  this time I’m not going to wait for him.
  • Congratulations! Your performance was excellent as usual.

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