A babe in arms is a very young child, or a person who is very young to be holding a position.
A babe in the woods is a naive, defenceless, young person.
(USA) A baby boomer is someone born in the years after the end of the Second World War, a period when the population was growing very fast.
If an issue is on the back burner, it is being given low priority.
(UK) If you are on your back foot, you are at a disadvantage and forced to be defensive of your position.
Something that's a back number is dated or out of fashion.
If you back the wrong horse, you give your support to the losing side in something.
If things happen back to back, they are directly one after another.
If you are back to square one, you have to start from the beginning again.
If you have to go back to the drawing board, you have to go back to the beginning and start something again.
If someone says they have to go back to the salt mines, they have to return, possibly unwillingly, to work.
If you have your back to the wall, you are in a difficult situation with very little room for manoeuvre.
A backseat driver is an annoying person who is fond of giving advice to the person performing a task or doing something, especially when the advice is either wrong or unwelcome.
A person who is bad and makes other bad is a bad apple.
If people feel hate because of things that happened in the past, there is bad blood between them.
A person who cannot be trusted is a bad egg. Good egg is the opposite.
If you're having a bad hair day, things are not going the way you would like or had planned.
(UK) When you are bad mouthing,you are saying negative things about someone or something.('Bad-mouth' and 'badmouth' are also used.)
If something's in bad shape, it's in bad condition. If a person's in bad shape, they are unfit or unhealthy.
If something leaves you with a bad taste in your mouth, you feel there is something wrong or bad about it.
"A bad worker always blames their tools" - If somebody does a job badly or loses in a game and claims that they were let down by their equipment, you can use this to imply that this was not the case.
Bag and baggage means all your possessions, especially if you are moving them or leaving a place.
If someone is a bag of bones, they are very underweight.
If someone is a bag of nerves, they are very worried or nervous.
A Baker's dozen is 13 rather than 12.
A person who is completely bald is as bald as a coot.
If the ball is in your court, it is up to you to make the next decision or step.
When the balloon goes up, a situation turns unpleasant or serious.
A ballpark figure is a rough or approximate number (guesstimate) to give a general idea of something, like a rough estimate for a cost, etc.
(USA) If you do something balls to the wall, you apply full acceleration or exertion.
Banana republic is a term used for small countries that are dependent on a single crop or resource and governed badly by a corrupt elite.
(UK) A banana skin is something that is an embarrassment or causes problems.
An area or an industry, profession, etc, where rules and laws are ignored or flouted is bandit territory.
A baptism of fire was a soldier's first experience of shooting. Any unpleasant experience undergone, usually where it is also a learning experience, is a baptism of fire.
A bar fly is a person who spends a lot of time drinking in different bars and pubs.
If you bare your heart to someone, you tell them your personal and private feelings. ('Bare your soul' is an alternative form of the idiom.)
A barefaced liar is one who displays no shame about lying even if they are exposed.
Someone who's bark is worse than their bite may well get angry and shout, but doesn't take action.
If you are barking up the wrong tree, it means that you have completely misunderstood something or are totally wrong.
This idiom means that someone is willing to get married.
(UK) A barrack-room lawyer is a person who gives opinions on things they are not qualified to speak about.
If someone's a barrel of laughs, they are always joking and you find them funny.
If something is a basket case, it is so bad that it cannot be helped.
If someone doesn't bat an eyelid, they don't react or show any emotion when surprised, shocked, etc.
If someone says they're waiting with bated breath, they're very excited and find it difficult to be patient.('Baited breath' is a common mistake.)
Someone with bats in the belfry is crazy or eccentric.
If you batten down the hatches, you prepare for the worst that could happen to you.
(USA) (from baseball) It means to do something perfectly.
A battle of nerves is a situation where neither side in a conflict or dispute is willing to back down and is waiting for the other side to weaken. ('A war of nerves' is an alternative form.)
If you are all ears, you are very eager to hear what someone has to say
If you get things that you desire, there may be unforeseen and unpleasant consequences.('Be careful what you wish for, lest it come true.' and 'Be careful what you wish for; you may receive it.' are also used.)
If you're on the pig's back, you're happy / content / in fine form.
If people are out in force, they are present somewhere in large numbers.
(USA) To be out in left field is not to know what's going on. Taken from baseball, when youngsters assign less capable players to the outfield where the ball is less likely to be hit by a young player. In business, one might say, 'Don't ask the new manager; he's out in left field and doesn't know any answers yet.'
Be that as it may is an expression which means that, while you are prepared to accept that there is some truth in what the other person has just said, it's not going to change your opinions in any significant manner.
If a person/object/situation is considered to be 'true blue', it is considered genuine.
(UK) If a woman is up the spout, she is pregnant.
Something someone says when they want to get out of a place or situation, meaning 'Get me out of here!'. (It comes from the TV series and movies Star Trek, though the exact words used were a little different.)
A bean counter is an accountant.
If something bears fruit, it produces positive results.
A bear market is a period when investors are pessimistic and expect financial losses so are more likely to sell than to buy shares.
People who bear the brunt of something endure the worst of something bad.
If you confront a powerful or dangerous rival on their territory, you are bearding the lion in his own den.
If someone doesn't say clearly what they mean and try to make it hard to understand, they are beating about (around) the bush.
(USA) If you beat someone to the draw, you do something before they do.
If people beat swords into ploughshares, they spend money on humanitarian purposes rather than weapons. (The American English spelling is 'plowshares')
If someone beats the daylights out of another person, they hit them repeatedly. ('Knock' can also be used and it can be made even stronger by saying 'the living daylights'.)
If you beat the rap, you escape conviction and punishment for a crime or something you have done wrong.
When you want to beat the tar out of someone, you want to beat them up badly.
If you beat someone to the punch, you act before them and gain an advantage.
If you beat your brains out, you think hard about something but cannot solve, understand or remember it.
(USA) If someone is trying to convince people to do or feel something without any hope of succeeding, they're beating a dead horse. This is used when someone is trying to raise interest in an issue that no-one supports anymore; beating a dead horse will not make it do any more work.
Beauty is in the eye of the beholder means that different people will find different things beautiful and that the differences of opinion don't matter greatly.
This idiom means that appearances can be deceptive and something that seems or looks good may turn out to be bad.
Someone who does everything for you, no matter when you ask, is at your beck and call.
Someone with bedroom eyes has a sexy look in their eyes.
If someone is very excited about something, they have a bee in their bonnet.
If something is the bee's knees, it's outstanding or the best in its class.
If you make a beeline for a place, you head there directly.
Someone who says they've been around the block a few times is indicating that they have life experience relating to the topic at hand. It is not necessary to discuss the introductory aspects of the topic or give beginner level advice.
(UK) If someone has been in the wars, they have been hurt or look as if they have been in a struggle.
People say this when they have already experienced what is being discussed.
(UK) People say that life is not all beer and skittles, meaning that it is not about self-indulgence and pleasure.
If people make an agreement or contract and then the situation changes very quickly, it changes before the ink is dry.
The term Jack Robinson represents 'a short amount of time'. When you do something before you can say Jack Robinson, you do it very quickly.
(UK) If something happens before you can say knife, it happens very quickly.
In philosophy "to beg the question" is to assume something to be true that has not yet been proved. I have seen the idiom also to mean that a question is crying out to be asked.
This idiom means that people who are in great need must accept any help that is offered, even if it is not a complete solution to their problems.
When someone is behind bars, they are in prison.
If something happens away from the public eye, it happens behind closed doors.
If you do something behind someone's back, you do it without telling them.
If you are behind the curve, you are behind or out of touch with current trends or developments. ('Ahead of the curve' iis the opposite)
A difficult position from which it is unlikely one can escape.
Someone that is behind the times is old-fashioned and has ideas that are regarded as out-dated.
A belief in the hereafter is a belief in the afterlife, or life after death. It is, therefore, associated with religions and the soul's journey to heaven or to hell, whichever way being just deserts for the person based on how they led their life.
This is an emphatic way of saying 'believe me'.
To bell the cat is to perform a difficult or impossible task.
Bells and whistles are attractive features that things like computer programs have, though often a bit unnecessary.
(USA) To be somewhere with bells on means to arrive there happy and delighted to attend.
If things go belly up, they go badly wrong.
If something isn't up to standard, or someone isn't feeling or doing very well, they are below par.
If someone says something that is cruel or unfair, it is below the belt, like the illegal punches in boxing.
(UK) Someone who wears belt and braces is very cautious and takes no risks.
(USA) Someone who wears belt and suspenders is very cautious and takes no risks.
If someone bends over backwards, they do everything they can to help someone.
To bend someone's ear is to talk to someone about something for a long-enough period that it becomes tiresome for the listener.
The Benjamin of the family is the youngest child.
(UK) A person who is as bent as a nine bob note is dishonest. The reference comes from pre-decimalisation in UK (1971), when a ten shilling (bob) note was valid currency but no such note as nine shillings existed.
If something is beside the point, it's not relevant to the matter being discussed or considered.
If people are beside themselves, they are very worried or emotional about something.
If you are beside yourself, you are extremely angry.
The best that could be obtained from a list of options that were not exactly what was required.
If you have the best of both worlds, you benefit from different things that do not normally go together.
If something is the best thing since sliced bread, it is excellent. ('The greatest thing since sliced bread' is also used.)
If you bet the farm, you risk everything on something you think will succeed.
(USA) If you bet the ranch, you risk everything on something you think will succeed.
(USA) If you can bet your bottom dollar on something, you can be absolutely sure about it.
This means that it is better to be the head or at the top of something that isn't very important or prestigious than a small or unimportant member of something big.
Your better half is your husband or wife.
This idiom suggests that doing something late is better than not doing it at all.
This idiom is used to recommend being cautious rather than taking a risk.
If something is better than a kick in the teeth, it isn't very good, but it is better than nothing.
If something is better than a stick in the eye, it isn't very good, but it is better than nothing.
This is the shortened form of the full idiom, 'better the devil you know than the devil you don't', and means that it is often better to deal with someone or something you are familiar with and know, even if they are not ideal, than take a risk with an unknown person or thing.
If you are caught between a rock and a hard place, you are in a position where you have to choose between unpleasant alternatives, and your choice might cause you problems; you will not be able to satisfy everyone.
If you are caught between the devil and the deep blue sea, you are in a dilemma; a difficult choice.
This idiom is used when telling someone something that you want them to keep secret.
If something's beyond a shadow of a doubt, then absolutely no doubts remain about it.