English Idioms & Idiomatic Expressions beginning with "J"

Jack Frost

If everything has frozen in winter, then Jack Frost has visited.

Jack the Lad

A confident and not very serious young man who behaves as he wants to without thinking about other people is a Jack the Lad.

Jack-of-all-trades

A jack-of-all-trades is someone that can do many different jobs.

Jam on your face

If you say that someone has jam on their face, they appear to be caught, embarrassed or found guilty.

Jam tomorrow

(UK) This idiom is used when people promise good things for the future that will never come.

Jane Doe

Jane Doe is a name given to an unidentified female who may be party to legal proceedings, or to an unidentified person in hospital, or dead. John Doe is the male equivalent.

Jekyll and Hyde

Someone who has a Jekyll and Hyde personality has a pleasant and a very unpleasant side to the character.

Jersey justice

(UK) Jersey justice is very severe justice.

Jet set

Very wealthy people who travel around the world to attend parties or functions are the jet set.

Jet-black

To emphasise just how black something is, such as someone's hair, we can call it jet-black.

Job's comforter

Someone who says they want to comfort, but actually discomforts people is a Job's comforter. (Job's is pronounced 'jobes', not 'jobs')

Jobs for the boys

Where people give jobs, contracts, etc, to their friends and associates, these are jobs for the boys.

Jockey for position

If a number of people want the same opportunity and are struggling to emerge as the most likely candidate, they are jockeying for position.

Jog my memory

If you jog someone's memory, you say words that will help someone trying to remember a thought, event, word, phrase, experience, etc.

John Doe

John Doe is a name given to an unidentified male who may be party to legal proceedings, or to an unidentified person in hospital, or dead. Jane Doe is the female equivalent.

John Hancock

(USA) John Hancock means a signature- his signature on the engrossed copy of the Declaration of Independence is very prominent.

John Q Public

(USA) John Q Public is the typical, average person.

Johnny on the spot

A person who is always available; ready, willing, and able to do what needs to be done.('Johnny-on-the-spot' is also used.)

Johnny-come-lately

A Johnny-come-lately is someone who has recently joined something or arrived somewhere, especially when they want to make changes that are not welcome.

Join the club

Said when someone has expressed a desire or opinion, meaning "That viewpoint is not unique to you". It can suggest that the speaker should stop complaining since many others are in the same position. Example: "If this train doesn't come, I'll be late for work!"  "Join the club!"

Joined at the hip

If people are joined at the hip, they are very closely connected and think the same way.

Judge, jury and executioner

If someone is said to be the judge, jury, and executioner, it means they are in charge of every decision made, and they have the power to be rid of whomever they choose.

Juggle frogs

If you are juggling frogs, you are trying to do something very difficult.

Jump down someone's throat

If you jump down someone's throat, you criticise or chastise them severely.

Jump on the bandwagon

If people jump on the bandwagon, they get involved in something that has recently become very popular.

Jump ship

If you leave a company or institution for another because it is doing badly, you are jumping ship.

Jump the broom

To jump the broom is to marry. (Jump over the broom, jump over the broomstick, jump the broomstick are also used.)

Jump the gun

If you jump the gun, you start doing something before the appropriate time.

Jump the shark

Said of a salient point in a television show or other activity at which the popularity thereof begins to wane: The Flintstones jumped the shark when a man from outer space came to visit them. The expression derives from an episode of the television sitcom 'Happy Days' in which Fonzie, clad in leather jacket and on water skis, jumps over a shark. That episode was widely seen as the beginning of the end for the formerly popular series.

Jump the track

Jumping the track is suddenly changing from one plan, activity, idea, etc, to another.

Jump through hoops

If you are prepared to jump through hoops for someone, you are prepared to make great efforts and sacrifices for them.

Jump to a conclusion

If someone jumps to a conclusion, they evaluate or judge something without a sufficient examination of the facts.

Jumping Judas!

An expression of surprise or shock.

Jungle out there

If someone says that it is a jungle out there, they mean that the situation is dangerous and there are no rules.

Jury's out

If the jury's out on an issue, then there is no general agreement or consensus on it.

Just around the corner

If something is just around the corner, then it is expected to happen very soon.

Just as the twig is bent, the tree’s inclined

Things, especially education, that affect and influence us in our childhood shape the kind of adult we turn out to be.  (There are various versions of this, like 'As the twig is bent, the tree's inclined' and 'As the twig is bent, so the tree inclines', 'As the twig is  bent so is the tree inclined')    

Just coming up to

If the time is just coming up to nine o'clock, it means that it will be nine o'clock in a very few seconds. You'll hear them say it on the radio in the morning.

Just deserts

If a bad or evil person gets their just deserts, they get the punishment or suffer the misfortune that it is felt they deserve.

Just for the heck of it

When someone does something just for the heck of it, they do it without a good reason.

Just for the record

If something is said to be just for the record, the person is saying it so that people know but does not necessarily agree with or support it.

Just in the nick of time

If you do something in the nick of time, you just manage to do it just in time, with seconds to spare.

Just off the boat

If someone is just off the boat, they are naive and inexperienced.

Just what the doctor ordered

If something's just what the doctor ordered, it is precisely what is needed.

Justice is blind

Justice is blind means that justice is impartial and objective.