plain
US /pleɪn/
UK /pleɪn/

1.
not decorated or elaborate; simple or ordinary in character
:
•
She prefers plain clothes without any patterns.
•
The instructions were written in plain language.
2.
3.
(of a woman) not beautiful or attractive
:
•
She was a rather plain woman, but very kind.
•
Despite her plain appearance, she had a captivating personality.