above the law

Meaning: If someone is above the law, they are not subject to the laws of a society.

For example:

• Just because his father is a rich and powerful man, he seems to think he's above the law and he can do whatever he likes.
  
• In a democracy, no-one is above the law - not even a president or a prime-minister.

 above board

Meaning: If something is above board, it's been done in a legal and honest way.

For example:

• I'm sure the deal was completely above board as I know James well and he'd never do anything illegal or corrupt.
• The minister claimed all the appointments were above board and denied claims that some positions had been given to his friends.

Origin: Possibly derived from card playing and the fact that card players who keep their hands above the table (or above "the board") can be seen to be playing honestly, without cheating.

 across the board

Meaning: If something is across the board, it relates to all without exception.

For example:

• The company has promised to increase salaries across the board, so everyone will get a pay rise.
  
• The tax cuts will only apply to low and middle-income families, so they won't be across the board.
  

Origin: From horse-racing, when bookmakers used to mark up the odds on large boards. An "across the board" bet was one in which equal amounts were bet on the same horse to win, place, or show. 

 Achilles' heel

Meaning: An Achilles' heel is a weakness that could result in failure.

For example:

• He's a good golfer, but his Achilles' heel is his putting and it's often made him lose matches.
  
• The country's dependence on imported oil could prove to be its Achilles' heel if prices keep on rising.
  

Origin: From the ancient Greek myth of Achilles whose mother made him invulnerable to attack by dipping him headfirst into a sacred river when he was a baby. She was holding him by one foot, and the heel of this foot wasn't touched by the water so it became his "weak point" later in life.

 against all odds | against all the odds

Meaning: If you do something against all odds, or against all the odds, you do it even though there were many problems and it didn't seem possible to do.

For example:

• He had a serious accident and was close to death but, against all odds, he recovered and now he's fine.
  
• No-one thought we could do it but, against all the odds, we won the Olympic gold medal. 

 add insult to injury

Meaning: Someone adds insult to injury if they say or do something to upset you a second time, after you've already been upset somehow.

For example:

• He said my clothes didn't suit me, and then to add insult to injury he said I needed to lose some weight!
  
• The bank took back my car, and then added insult to injury by cancelling my credit cards!

 add fuel to the fire

Meaning: If you add fuel to the fire, you do something to make a bad situation even worse.

For example:

• People are already unhappy, and if the government allows oil prices to increase it'll just be adding fuel to the fire.
  
• If Billy's angry, don't say anything. You'll just be adding fuel to the fire.
  

Origin: Probably metaphorical, from the fact that adding a fuel, like petrol or wood, to a fire will make it burn brighter and hotter.

 all hell broke loose - Informal

Meaning: You can say "all hell broke loose" if a situation suddenly became violent or chaotic.

For example:

• I was walking through the station on my way to work when I heard this huge explosion, and then all hell broke loose.
  
• Everything was fine in the club until someone yelled, "Fire!" and then all hell broke loose as people started running and screaming and pushing each other.

 ahead of the game

Meaning: You are ahead of the game if you have an advantage over your competitors in any activity in which you try to do better than others, such as in business, academia, sports, etc.

For example:

• We got ahead of the game by employing the best people in our research laboratories.
  
• You'll be ahead of the game when you start at university if you do a lot of preparation before the term begins.

 agree to differ | agree to disagree

Meaning: If two people agree to differ, or agree to disagree, they accept that they have different opinions about something and stop trying to change each other's opinion.

For example:

• We're never going to think the same way about politics, so let's just agree to differ and leave it at that.
  
• Why don't they just agree to disagree instead of arguing about it all the time?

 an acid test

Meaning: An acid test is something that shows the true worth or value of something or someone.

For example:

• Our new player has been doing well at training and in practice matches, but the acid test will come in her first real match.
  
• The new political party is doing better and better in the polls, but the acid test will be the next election.
  

Origin: Possibly related to the fact that a test involving acid has been used for over a century to prove that a metal that looks like gold is, or is not, really gold. 

 all the rage Informal

Meaning: If something is all the rage, it's very popular or it's in fashion at the moment.

For example:

• Can you remember when disco was all the rage and we'd go dancing all night in the clubs?
  
• When Hans was a kid, skate boards were all the rage.

an axe to grind (2) British English

 an axe to grind (2)

Meaning: If you have an axe to grind, you have a strong opinion about something and you express this opinion whenever you can.

For example:

• Billy's had this axe to grind about globalisation recently and he's always going on about it.
  
• These people always seem to have an axe to grind and whenever someone interviews them they see it as a chance to push their ideas.
  

Note: This idiom has at least two meanings, and the meaning given here is used mostly in British English. See "an ax to grind (1)" for another meaning that is used more in American English.

Variety: This idiom is typically used in British English but may be used in other varieties of English too.

an ax to grind (1) American English

 an ax to grind (1)

Meaning: If you have an ax to grind with someone, you have a problem with them, or a complaint against them, which you'd like to discuss.

For example:

• I have an ax to grind with Mitch. He owes me money and he's been avoiding me.
  
• If Larry has an ax to grind with someone, and he meets them after he's been drinking, he can get violent.
  

Note: 1. The spelling "ax", as opposed to "axe", is the more common spelling in American English. 2. Another idiom with a similar meaning is "to have a bone to pick" with someone.

Variety: This idiom is typically used in American English but may be used in other varieties of English too.

 an act of God Formal

Meaning: Something like an earthquake or a tornado can be called an act of God.

For example:

• Will your insurance policy pay for the cost of replacing your house if it's destroyed by an act of God?
  
• My daughter said that if disasters that kill lots of people are acts of God, why does He do it. I didn't know what to say.
  

Origin: The phrase 'act of God' originally appeared in religious texts, though nowadays it is mostly found in legal texts. 

 around the clock

Meaning: If something occurs around the clock, it goes on all day and all night.

For example:

• I have to finish this report by Tuesday, so I'll be working around the clock until I get it done.
  
• What the young people of this town need is a drop-in centre that's open around the clock.

 answer the call of nature

Meaning: If you answer the call of nature, you go to the toilet.

For example:

• Could we stop somewhere? I need to answer the call of nature.
  
• Does anyone need to answer the call of nature before we set off?

another string to your bow British English

 another string to your bow

Meaning: If you have another string to your bow, you have another way of making a living.

For example:

• Lots of people learn to teach English so they'll have another string to their bow.
  
• I've lost my job and I'll have to retrain for something else. I wish I already had another string to my bow.
  

Origin: Probably metaphorical, from the fact that if an archer has a spare string for their bow, they can still shoot an arrow even if their first string breaks.

Variety: This idiom is typically used in British English but may be used in other varieties of English too.

at a loose end British English

 at a loose end

Meaning: If you're at a loose end, you have nothing to do.

For example:

• If I'm ever at a loose end, I look for a good book to read.
  
• Give me a call if you're at a loose end and we'll go and do something.
  

Note: This is similar to the American idiom "at loose ends", though the American idiom seems to indicate a state of unhappy restlessness that results from having nothing to do, while the British idiom simply means having nothing to do.

Variety: This idiom is typically used in British English but may be used in other varieties of English too.

 asking for trouble

Meaning: If someone is asking for trouble, they're doing something risky that could lead to a problem.

For example:

• Don't you think that working all day and then partying all night is asking for trouble?
  
• Running fast without warming up properly is asking for trouble, and could easily cause a muscle strain.