I

I hereby give notice of my intention
Hereby is used sometimes in formal, official declarations and statements to give greater force to the speaker’s or the writer’s affirmation. People will say it sometimes to emphasise their sincerity and correctness.
I should cocoa
This idiom comes from ‘I should think so’, but is normally used sarcastically to mean the opposite.
I’ll eat my hat
You can say this when you are absolutely sure that you are right to let the other person know that there is no chance of your being wrong.
I’ve got a bone to pick with you
If somebody says this, they mean that they have some complaint to make against the person they are addressing.
If you’ll pardon my French
This idiom is used as a way of apologising for swearing.
Ill-gotten gains
Ill-gotten gains are profits or benefits that are made either illegally or unfairly.
In a cleft stick
If you are in a cleft stick, you are in a difficult situation, caught between choices.
In a flash
If something happens in a flash, it happens very quickly indeed.
In a heartbeat
If something happens very quickly or immediately, it happens in a heartbeat.
In a jam
If you are in a jam, you are in some trouble.
In a jiffy
If something happens in a jiffy, it happens very quickly.
In a nutshell
This idiom is used to introduce a concise summary.
In a pickle
If you are in a pickle, you are in some trouble or a mess.
In a tick
If someone will do something in a tick, they’ll do it very soon or very quickly.
In all honesty
If you say something in all honesty, you are telling the complete truth. It can be used as a way of introducing a negative opinion whilst trying to be polite; in all honesty, I have to say that I wasn’t very impressed.
In an instant
If something happens in an instant, it happens very rapidly.
In cahoots
If people are in cahoots, they are conspiring together.
In cold blood
If something is done in cold blood, it is done ruthlessly, without any emotion.
In dire straits
If you’re in dire straits, you’re in serious trouble or difficulties.
In donkey’s years
‘I haven’t seen her in donkey’s years.’—This means for a very long time.
In dribs and drabs
If people arrive in dribs and drabs, they come in small groups at irregular intervals, instead of all arriving at the same time.
In droves
When things happen in droves, a lot happen at the same time or very quickly.
In for a penny, in for a pound
If something is worth doing then it is a case of in for a penny, in for a pound, which means that when gambling or taking a chance, you might as well go the whole way and take all the risks, not just some.
In full swing
If things are in full swing, they have been going for a sufficient period of time to be going well and very actively.
In my bad books
If you are in someone’s bad books, they are angry with you. Likewise, if you are in their good books, they are pleased with you.
In my book
This idiom means ‘in my opinion’.
In my good books
If someone is in your good books, you are pleased with or think highly of them at the moment.
In one ear and out the other
If something goes in one ear and out the other, you forget it as soon as you’ve heard it because it was too complicated, boring etc.
In over your head
If someone is in over their head, they are out of the depth in something they are involved in, and may end up in a mess.
In rude health
If someone’s in rude health, they are very healthy and look it.
In stitches
If someone is in stitches, they are laughing uncontrollably.
In tandem
If people do things in tandem, they do them at the same time.
In the black
If your bank account is in credit, it is in the black.
In the club
If a woman’s in the club, she’s pregnant. ‘In the pudding club’ is an alternative form.
In the dock
If someone is in the dock, they are on trial in court.
In the doghouse
If someone is in the doghouse, they are in disgrace and very unpopular at the moment.
In the family way
If a woman is in the family way, she is pregnant.
In the hot seat
If someone’s in the hot seat, they are the target for a lot of unwelcome criticism and examination.
In the long run
This means ‘over a long period of time’, ‘in the end’ or ‘in the final result’.
In the offing
If something is in the offing, it is very likely to happen soon.
In the pink
If you are in very good health, you are in the pink.
In the pipeline
If something’s in the pipeline, it hasn’t arrived yet but its arrival is expected.
In the red
If your bank account is overdrawn, it is in the red.
In the same boat
If people are in the same boat, they are in the same predicament or trouble.
In the soup
If you’re in the soup, you’re in trouble.
In the swim
If you are in the swim, you are up-to-date with and fully informed about something.
In the swing
If things are in the swing, they are progressing well.
In the twinkling of an eye
If something happens in the twinkling of an eye, it happens very quickly.
In two minds
If you are in two minds about something, you can’t decide what to do.
In your face
If someone is in your face, they are direct and confrontational.
In your sights
If you have someone or something in your sights, they are your target to beat.
Indian file
If people walk in Indian file, they walk in a line one behind the other.
Indian giver
An Indian giver gives something, then tries to take it back.
Indian summer
If there is a period of warmer weather in late autumn, it is an Indian summer.
Into thin air
If something vanishes or disappears without trace, it vanishes into thin air; no-one knows where it has gone.
Iron fist
Someone who rules or controls something with an iron fist is in absolute control and tolerates no dissent.
Irons in the fire
A person who has a few irons in the fire has a number of things working to their advantage at the same time.
It ain’t over till the fat lady sings
This idiom means that until something has officially finished, the result is uncertain.
It cost an arm and a leg
If something costs an arm and a leg, it is very expensive indeed.
It cost the earth
If something costs the earth, it is very expensive indeed.
It’s no use crying over spilt milk
This idiom means that getting upset after something has gone wrong is pointless; it can’t be changed so it should be accepted.
Ivory tower
People who live in ivory towers are detached from the world around them.