Idiom / Saying Explanation

To do a complete one-eighty.

For example:-

The Liberal party did a complete one-eighty on tuition fees.

To turn around and go in the opposite direction.

To reverse a decision or opinion.

A nine/one/seven-day wonder

For example:-

Don't put your coats away just yet – yesterday's sizzling hot weather was a one-day wonder.

Someone or something that causes interest or excitement for a short period but is then quickly forgotten

A bird in the hand is worth two in the bush.

For example:-

I would stay with your current firm, rather than look for something better. After all, a bird in the hand is worth two in the bush.

Having something for certain is better than the possibility of getting something better.

First hand

For example:-

We can't experience poverty and misery first hand, but we can give to those who suffer from it.

If you experience something first hand, you experience it yourself.

Do a number on someone.

For example:-

The competition was fake and did a real number with my email address. It could take days to get rid of all the spam I got.

To treat someone very badly or unfairly.

One foot in the grave.

For example:-

She's been saying she has one foot in the grave for years now.

To be close to death, or so old you are likely to die soon 

One good turn deserves another 

For example:-

He fixed my computer, so I invited him to the party. One good turn deserves another.

If someone does something nice for you, you should do something for that person in return.

A one horse town.

For example:-

The town I grew up in was a one-horse town. I couldn't wait to move.

A very small town. (Usually negative.)

One step ahead

For example:-

The police hunted him for years, but he always managed to stay one step ahead of them.

To be slightly better prepared or more successful than someone else.

Seven year itch

For example:-

Far too many couples suffer from the seven-year itch (which has been reduced these days to the two-year and even seven-month itch),

A real or imagined longing for other relationships in the seventh year of marriage.

To be at sixes and sevens

For example:-

I was trying to upload photos into my blog, but I was all at sixes and sevens, I didn't have a clue how to do it!

Used to describe a state of confusion or disarray.