U

U-turn
If a government changes its position radically on an issue, especially when they have promised not to do so, this is a U-turn.
Ugly duckling
An ugly duckling is a child who shows little promise, but who develops later into a real talent or beauty.
Uncharted waters
If you’re in uncharted waters, you are in a situation that is unfamiliar to you, that you have no experience of and don’t know what might happen.
Uncle Sam
Uncle Sam is the government of the USA.
Under a cloud
If someone is suspected of having done something wrong, they are under a cloud.
Under false colours
If someone does something under false colours, they pretend to be something they are not in order to deceive people so that they can succeed.
Under fire
If someone is being attacked and criticised heavily, they are under fire.
Under the radar
If something slips under the radar, it isn’t detected or noticed.
Under the table
Bribes or illegal payments are often described as money under the table.
Under the weather
If you are feeling a bit ill, sad or lack energy, you are under the weather.
Under the wire
If a person does something under the wire, they do it at the last possible moment.
Under your breath
If you say something under your breath, you whisper or say it very quietly.
Under your nose
If something happens right in front of you, especially if it is surprising or audacious, it happens under your nose.
Unwavering loyalty
Unwavering loyalty does not question or doubt the person or issue and supports them completely.
Up in the air
If a matter is up in the air, no decision has been made and there is uncertainty about it.
Up sticks
If you up sticks, you leave somewhere, usually permanently and without warning.
Up the ante
If you up the ante, you increase the importance or value of something, especially where there’s an element of risk as the term comes from gambling, where it means to increase the amount of money bet.
Up the creek
If someone or something is up the creek, they are in real trouble.
Up the duff
If a woman is up the duff, she’s pregnant.
Up the spout
If something has gone up the spout, it has gone wrong or been ruined.
Up the stick
If a woman is up the stick, she’s pregnant.
Up the wall
If someone goes up the wall, they get very angry.
Up to scratch
If something doesn’t come up to scratch, it doesn’t meet the standard required or expected.
Up to snuff
If something isn’t up to snuff, it doesn’t meet the standard expected.
Up to speed
If you bring someone up to speed, you update him on something.
Up to the neck
If someone’s in something up to the neck, they are very involved in it, especially when it’s something wrong.
Upper crust
The upper crust are the upper classes and the establishment.
Upper hand
If you have the upper hand, you have the advantage.
Upset the apple cart
If you upset the apple cart, you cause trouble and upset people.