This is the 14055th most frequent Russian word.
однотонная
Monochromatic or solid-colored.
однотонная describes the blouse as having a single, uniform color.
У неё была однотонная голубая блузка.
She had a solid blue blouse.
однотонного describes the tone of the wallpaper as uniform and singular.
Мы выбрали обои для комнаты однотонного кремового оттенка.
We chose wallpaper for the room of a solid cream tone.
Однотонные refers to fabrics characterized by a singular, uniform color scheme.