Plain means something is simple. It does not have decorations or special designs. It looks basic and clear.
She wore a plain blue dress.
The room is plain and small.
When something is plain, it means it is very clear or easy to see. People can understand it without any problem.
It is plain that he is happy.
The answer was plain to everyone.
When a person is plain, they speak or act in an honest and clear way. They do not hide their thoughts or feelings.
She gave a plain answer to the question.
His plain words show he is truthful.
To plain (rare verb) means to make something clear or easy to understand. It is used when explaining information simply.
He plained his idea to the team.
She plained the rules very well.
