Explain it in plain words.

I prefer plain knitting when I make sweaters.

The Olympic Games originated in Olympia, a plain in the western part of the Peloponnese peninsula in Greece.

The plainness of her words made it clear that she was not happy.

I prefer plain chocolate without any added sugar.

Plain dealing is essential in business transactions.

You can use plain flour instead of self-raising flour.

The project has been plain sailing so far.

Plains Indian tribes relied on buffalo for their survival.

It was as plain as day that he was lying.