1 simple/not decorated
VERBS be, look, seem
ADV. extremely, very | absolutely, completely The dress was absolutely plain, but quite stunning. | fairly, quite, rather The food was fairly plain, but well cooked.
PHRASES plain blue, white, etc. a plain white shirt
2 not beautiful
VERBS be, look
ADV. extremely, very She looked very plain and dowdy. | rather a rather plain woman
VERBS be, seem | become | make sth They made it plain that they were against the idea.
ADV. very | absolutely, perfectly, quite Within weeks, it became perfectly plain that we were in the grip of a tyrant. | increasingly | fairly, pretty, reasonably
PREP. to It is all quite plain to me.
ADJ. open The horses galloped across the open plains. | rolling, sweeping miles of rolling plain, made fertile by the river | great, unbroken, vast | flat | fertile fertile plains suitable for farming | grassy | coastal
PREP. across a/the ~ Cattle move freely across the grassy plain. | in a/the ~ the Olduvai Gorge in the vast plain of Tanzania | on a/the ~ Nothing grew on the plain.