The UX of the app is really clunky.

When I went to buy a can of coffee from the vending machine, it came out with a clunk.

This car is a clunker.

I'm not going there in that clunker.

You'll spot him in his downmarket clothes and his clunker of a car.

There was an old clunker parked just behind my new sports car.

It's old and clunky.

Tom thinks that the new reddit app is much clunkier than the one he's currently using.

Such a clunker!

His old clunker isn't worth anything.