bezużyteczny in English:

I wish I had not bought such a useless thing.

Don't waste your allowance on useless things.

The Internet has a lot of information and thus also a lot of useless information.

We're useless.

He regards so-called compulsory education as useless.

I have one of my friends who graduated from university and became a fine public servant. Once he told me that what he had learned from school had been useless. However, what little philosophy he had learned proved to be of great benefit.

For once in my life I'm doing a good deed... And it is useless.

The retired often feel that they are useless and unproductive.

John claimed that the dishonest salesman had tricked him into buying a useless piece of machinery.

She caught sight of the tautology that she was looking for in a crowd of other, equally useless and potentially dangerous, tautologies.

Of course you can't say that it's worth nothing because it isn't perfect, so that doesn't mean that GTD is useless.

The number one reason why friends dump their friends on Facebook is too many useless posts.

Nail polish is useless: no one looks at nails anyway.

Making a clean separation between the "useful" and the "useless" is about as straightforward as drawing the fine line between water and ice.

The equipment you sent me is completely unusable.

This old computer is unusable.