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

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

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

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

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

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

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.

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.

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.

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

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

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

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

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.

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

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

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

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

If you do something as soon as possible (sometimes abbreviated to "asap"), you do it at the first possible opportunity.

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

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

If you're at cross-purposes with someone, you think you're both talking about the same thing but you're actually talking about different things.

If you're at loose ends, you feel restless and unsettled because you don't have anything to do.

If you're at sea, or all at sea, you're confused about something and not sure what to do.

If you do something at the drop of a hat, you do it immediately, without preparation or planning.

If you're at your wits' end, you're upset and frustrated because you've tried everything you can think of to solve a problem, and nothing has worked.

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