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Using adjectives, especially colours, to describe things is a quick and easy way to build your lexical resource for the IELTS Speaking and Writing tests. In addition to their traditional use as adjectives, colours also feature in some popular idioms. But unlike adjectives, colours in idioms have symbolic historical/cultural connotations, and are not to be taken literally. Let’s look at some examples and learn some idioms that use the colours ‘blue’ and ‘black’.

out of the blue

(suddenly or unexpectedly)

My old school friend Sally rang me yesterday out of the blue. It was a bit of shock as I hadn’t heard from her in years.

do something until you are blue in the face

(do something with a great amount of effort, but it has no effect)

I explained to my parents why it was so important for me to go to that party until I was blue in the face, but they still refused to let me go.


(describes a manual worker)

Unfortunately, a lot of the blue-collar workers lost their jobs because the factory decided to introduce some new automated machinery.

once in a blue moon

(something that hardly happens)

When I do go back to my home country for a visit, I prioritise seeing my family first as I can’t stay for long.  I only catch up with my old school friends once in a blue moon because of that.

feel blue

(feel down/sad)

When my best friend moved to another city for university, I felt a little blue for a while because I missed him quite a lot.

black sheep

(someone who is either very different or a bad member of a group)

I’m the only person in my whole family who became an artist.  All of the others are either doctors, lawyers or engineers, so I’m kind of the black sheep of the family.

black and white

(when something is very clearly explained or written down)

They made a great job offer to me over the telephone, but I wasn’t going to accept it until I had seen all of the details in black and white in a contract.

black mark / black mark next to your name

(when there is a record of someone’s negative behaviour)

I always make sure I attend staff meetings with the upper management on time. As I’m new to the company, the last thing I want is to have a black mark next to my name.

black and blue

(when you are hurt emotionally or have physical bruises)

After falling off my bicycle when I was speeding downhill, I was black and blue for nearly two weeks.


Idioms with colours are easy to remember and if used correctly, help you add more impact to your sentences. As a next step, can you think of some idioms that use the colour ‘red'? Share your answers on Facebook, Twitter, Instagram and TikTok using the hashtags #IELTSIDP #RedIdioms