jack-of-all-trades

- a person who can do many things

We gave him a job because we needed a jack-of-all-trades around the factory to look after the many repairs.

jack up

- raise prices

The gas station jacked up their prices during the snow storm.

jam on the brakes

- quickly put the brakes on in a car to stop

He jammed on the brakes and was able to avoid hitting the child.

jam-packed

- crowded, full

The train that we took this morning was jam-packed with people.

jazz up

- brighten up, add more noise or movement or color

They really jazzed up the community center for the party tonight.

John Doe

- name used for an unknown person

Why do the application forms use "John Doe" as the name of the person who is applying for something?

John Henry (John Hancock)

- signature

Please sign your John Henry here and we will process your order right away.

Johnny-come-lately

- new-comer

He`s a Johnny-come-lately and doesn`t really know what he is talking about.

Johnny-on-the-spot

- be at the right place when needed, right on time

He`s always Johnny-on-the-spot. Just when we need him he arrives.

jump all over someone

- criticize, scold, blame

As soon as I began to talk about my plans for the summer he jumped all over me.

jump at

- take or accept quickly and gladly

He jumped at the chance to go to Europe on company business.

jump bail

- run away and fail to come to trial and give up the money you have already paid to the court

He jumped bail and decided to go and live in a foreign country.

jump down someone`s throat

- criticize or become angry with someone

As soon as I reached the office he jumped down my throat over the missing file.

jumping-off place

- the starting place of a long trip

We gathered early in the morning at the jumping-off place for our trip to the mountains.

jump on someone

- scold, criticize, blame

Everyone jumped on him at the meeting because they were angry about the new schedules.

jump on the bandwagon (also get or climb on the bandwagon)

- join a popular activity

Everyone has jumped on the bandwagon to try and stop smoking in the workplace.

jump out of one`s skin

- be badly frightened

I nearly jumped out of my skin when I saw him at the window.

jump the gun

- start before you should

He jumped the gun and started selling the tickets before he should.

jump through a hoop

- do whatever one is told to do, obey any order

He is always ready to jump through a hoop for his boss so he is not very popular with the other employees.

jump to conclusions

- make a quick conclusion without thinking

Please don`t jump to conclusions over who broke the computer.

just about

- nearly, almost

I waited just about one hour before the concert started.

just now

- this very moment, a minute ago

The accident happened just now. The police haven`t even arrived yet.

just so

- with great care, very carefully

She always makes sure that her hair is just so before she goes out.

just the same

- nevertheless

I told her not to come early but just the same she came early anyway.

just what the doctor ordered

- exactly what is needed or wanted

Having the extra day off from work was just what the doctor ordered and he was able to get his many errands finished.