Y

Yah boo sucks
Yah boo & yah boo sucks can be used to show that you have no sympathy with someone.
Yellow press
The yellow press is a term for the popular and sensationalist newspapers.
Yellow streak
If someone has a yellow streak, they are cowardly about something.
Yellow-bellied
A yellow-bellied person is a coward.
Yen
If you have a yen to do something, you have a desire to do it.
Yes-man
Someone who always agrees with people in authority is a yes-man.
Yesterday’s man
Someone, especially a politician or celebrity, whose career is over or on the decline is yesterday’s man.
You can lead a horse to water, but you can’t make it drink
This idiom means you can offer something to someone, like good advice, but you cannot make him take it.
You can say that again
If you want to agree strongly with what someone has said, you can say ‘You can say that again’ as a way of doing so.
You can’t have your cake and eat it
This idiom means that you can’t have things both ways.
You can’t make a silk purse out of a sow’s ear
If something isn’t very good to start with, you can’t do much to improve it.
You can’t make an omelette without breaking eggs
This idiom means that in order to achieve something or make progress, there are often losers in the process.
You scratch my back and I’ll scratch yours
This idiom means that if you do something for me, I’ll return the favour.
You what?
This is a very colloquial way of expressing surprise or disbelief at something you have heard. It can also be used to ask someone to say something again.
Young blood
Young people with new ideas and fresh approaches are young blood.
Young Turk
A Young Turk is a young person who is rebellious and difficult to control in a company, team or organisation.
Your name is mud
If someone’s name is mud, then they have a bad reputation.