afraid of one’s own shadow

A person who is afraid of his/her own shadow is very nervous or easily frightened.
“I’ve never seen anyone so easily scared. She’s afraid of her own shadow!”

bated breath

If you wait for something with bated breath, you are both anxious and excited about an imminent event.
“We waited with bated breath for the winner to be announced.”

make your blood run cold

If something makes your blood run cold, it shocks or scares you a lot.
“The look in the prisoner’s eye made my blood run cold!

break out in a cold sweat

If you break out in a cold sweat, you begin to perspire a lot, usually from anxiety.
“I get nervous at the dentist’s and usually break out in a cold sweat.”

bundle of nerves

If you describe someone as a bundle of nerves, you mean that they are very nervous, tense or worried.
“My son is doing his driving test today. Needless to say he’s a bundle of nerves!”

(have) butterflies in stomach

If you have butterflies in your stomach, you are feeling very nervous.
“At the beginning of an exam, I always have butterflies in my stomach.”

can’t stand the pace

If you can’t stand the pace, you are unable to do things well when there is a lot of pressure.
“She once worked for a famous fashion designer but she couldn’t stand the pace.”

(like a) cat on hot bricks

A person who is like a cat on hot bricks is very nervous or restless.
“The week before the results were published, she was like a cat on hot bricks.”

on the edge of one’s seat

Someone who is on the edge of their seat is very interested in something and fits it both extremely exciting and nerve-wracking.
“Look at Bob! He’s on the edge of his seat watching that rugby match!”

get one’s fingers burnt

If someone gets their fingers burnt, they suffer as a result of an unsuccessful action and are nervous about trying again.
“He got his fingers burnt so badly in the last elections that he decided to withdraw from politics.”

heart in one’s mouth

A person who has their heart in their mouth feels extremely anxious or nervous faced with a dangerous or unpleasant situation.
“Emma had her heart in her mouth when she saw her two-year-old son standing in front of the open window.”

heart misses a beat

If your heart misses (or skips) a beat, you have sudden feeling of fear or excitement.
“When the lights suddenly went out, my heart missed a beat.”

heebie-jeebies

A state of apprehension, nervousness or anxiety is called the heebie-jeebies.
“Having to go down to the car park at night gives me the heebie-jeebies.”

hold your breath

If someone is holding their breath, they are waiting anxiously or excitedly for something to happen or be announced.
“I went for a second interview today – now I’m holding my breath!”

if you can’t stand the heat, get out of the kitchen

This expression means that if you feel that there is too much pressure, you can leave.
Amid the growing tension, the organiser declared : “If you can’t stand the heat, get out of the kitchen!”

ignorance is bliss

This means that if you don’t know about a problem or unpleasant fact, you won’t worry about it.
“I didn’t know our neighbour was an escaped prisoner until the police arrived – ignorance is bliss!”

get/have the jitters

If you get (or have) the jitters, especially before an important event, you become very nervous or anxious and begin to shake.
“Some people get the jitters when they have to make a speech.”

have kittens

To say that you’re going to have kittens is a dramatic way of expressing worry, anxiety or fear.
“His mother nearly had kittens when Alex announced that we wanted to be a trapeze artist.”

jump out of your skin

If you jump out of your skin, you are extremely surprised or shocked.
“Jane nearly jumped out of her skin when the horse put its head through the kitchen window!”

get your knickers in a twist

If you get your knickers in a twist, you are anxious, nervous, or angry faced with a difficult situation.
“Don’t get your knickers in a twist! Everything is under control.”

nerves of steel

Someone who has nerves of steel is not afraid and stays calm in difficult or dangerous situations.
“Fire-fighters need to have nerves of steel.”

on pins and needles

If you are on pins and needles, you are very anxious or nervous about what is going to happen.
“Scott was on pins and needles while he waited for the result of the exam.”

quaking in one’s boots

When someone is extremely scared, it is said that they are quaking in their boots.
“When he saw the crocodiles in the water, he started quaking in his boots.”

scare (someone) out of their wits

If something scares you out of your wits, it makes you very frightened or worried.
“The feeling that a house is haunted can scare people out of their wits.”

scare the daylights out of someone

If something scares the (living) daylights out of you, it terrifies you.
“The sudden screaming scared the daylights out of me. I was absolutely terrified!”

scared stiff

Someone who is scared stiff  is so frightened that they are unable to move.
“My mother is scared stiff of heights.”

shake like a leaf

If you shake like a leaf, you tremble with fear or nervousness.
“At the beginning of the interview the candidate was shaking like a leaf.

on tenterhooks

A person who is on tenterhooks is in a state of anxious suspense or excitement
“The candidates were kept on tenterhooks for hours while the panel deliberated.”

tongue-tied

If you are tongue-tied,you have difficulty in expressing yourself because you are nervous or embarrassed.
“At the start of the interview I was completely tongue-tied!”

whistle in the dark

If you whistle in the dark, you try to hide your fear and pretend to be brave in a scary or dangerous situation.
“Bob looks confident but he’s just whistling in the dark; he knows he’s going to lose his job.”

at your wits’ end

If you are at your wits’ end, you are so worried about something that you do not know what to do next.
“When her son dropped out of school, Susan was at her wits’ end.