('US') All kinds of people attended the event, including politicians, celebrities, and 'just plain folks'. [=ordinary people]
The answer is (as) 'plain as day'. = The answer is 'as plain as the nose on your face'. [=the answer is very obvious]
She describes herself as a 'plain Jane'. [=a woman who is ordinary looking and not beautiful or glamorous]
(..) Unless, of course, he had disagreements. - I mean, with government policy. - GRANDPA: One hears of such men. Disturbed, most of them, or just plain cowards. FATHER: Even so, all of them traitors. GRANDPA: Absolutely right. Presumably, if that was the case with your father, (..)2008 The Boy in the Striped Pajamas