compañero de piso in inglese:

Do you get on well with your flatmates?

Kevin is my flatmate.

They're flatmates and best friends.

Try not to wake up my flatmate

There are two bedrooms in my flat: I have one and my flatmate has the other one.

I'm fed up of tidying up after my flatmates!

My flatmate and I share all the costs of living in this flat.

My flatmate isn't friendly.

Wydaje mi się, że mój współlokator jest w domu. I think my flatmate is home.

I'm your flatmate Paul.

I am Paul, your flatmate.