Colloquialism or colloquial language might be used in casual communication but is inappropriate for formal use.
For example, do not use any of the following words:
- Handy
- Cheers
- Dodgy
- Folks
Most idioms are also colloquial and of are groups of words that only holds meaning for a subset of people. For example, do not use any of the following phrases:
- Cutting-edge technology
- Over the moon
- See the light
- He bit the bullet
- Let’s talk about the elephant in the room