in a way that is easy to understand or recognize:
Mrs Gorman was plainly delighted.
The first part of that argument is plainly true.
We could hear Tom's voice plainly over the noise of the crowd.
Plainly the laws are not effective.
speaking honestly, and without trying to hide the truth:
She told him plainly that she had no intention of marrying him.
simply or without decoration:
a plainly dressed young girl
The room was very plainly furnished.