100 Mistakes #4 - grow or grow up?

´Grow´ means ´increase in size` or ´become bigger`. If you water a plant, it will grow.

´Up` is a direction of movement, to a higher position.

´Grow up` is a verb made from these two words but its meaning is not a combination of the meanings of those words!

This is very frustrating if you`re learning English because you can sometimes know the meaning of the individual words without knowing the meaning of the combination.

´Grow up` does not mean ´become bigger with movement to a higher position`

´Grow up` means ´become an adult`.

It is, like many phrasal verbs, a metaphor. When you are a child, you think that getting bigger and getting older are the same thing.

Let´s look at some examples of using ´grow up`:

When I grow up, I want to be an astronaut.
I grew up in Northamptonshire.
Michael Jackson never really grew up.

"Have you heard the new Michael Jackson album?
"Ha ha, you said ´bum`!
"Oh, grow up!"

But not:

Last year, sales grew up by 25%.  They didn´t grow up, they grew.
The price of coffee has grown up again.
It hasn`t grown up, it has gone up. (Go up = increase.)