In this post, you're going to learn the idioms based on colours.
relating to people who do physical work in a factory, mine, etc.:
- The city is facing a shortage of blue-collar workers such as plumbers and electricians.
relating to jobs that are done in an office, bank, etc.:
- The company will cut 1.400 white-collar jobs.
In black and white
in a written or printed form:
- I want to put it in black and white.
Out of the blue
- His resignation came out of the blue.
Point the town red
to have a good time by going to a lot of bars or clubs:
- Let's paint the town red.
Like a red rag to a bull
American English: like waving a red flag in front of a bull
something that will make someone angry or upset:
- Don't tell him you are an Arsenal supporter – it's like a red rag to a bull.
Green with envy
feeling a desire to have what another person has:
- We are green with envy after she got the chance to study abroad.
a situation in which you are not sure how to define it or deal with it:
- The new rule has a lot of grey areas.
See: Idioms about happiness