plain

¹ American  

[pleyn] / pleɪn /

adjective

plainer, plainest

1. clear or distinct to the eye or ear: to stand in plain view.

   a plain trail to the river;

   to stand in plain view.

   Synonyms:

   perspicuous, apparent, unmistakable, intelligible, understandable, lucid

   Antonyms:

   indistinct

2. clear to the mind; evident, manifest, or obvious.

   to make one's meaning plain.

   Synonyms:

   transparent, patent, unequivocal, unambiguous, perspicuous, apparent, unmistakable, intelligible, understandable, lucid

   Antonyms:

   obscure

3. conveying the meaning clearly and simply; easily understood.

   plain talk.

   Synonyms:

   transparent, patent, unequivocal, unambiguous

4. downright; sheer; utter; self-evident.

   plain folly;

   plain stupidity.

5. free from ambiguity or evasion; candid; outspoken.

   the plain truth of the matter.

   Synonyms:

   sincere, open, ingenuous, frank, blunt, direct, straightforward, unreserved

6. without special pretensions, superiority, elegance, etc.; ordinary.

   plain people.

   Synonyms:

   unpretentious

7. not beautiful; physically unattractive or undistinguished.

   a plain face.

8. without intricacies or difficulties.

9. ordinary, simple, or unostentatious.

   Although she was a duchess, her manners were attractively plain.

10. with little or no embellishment, decoration, or enhancing elaboration.

    a plain blue suit.

11. without a pattern, figure, or device.

    a plain fabric.

12. not rich, highly seasoned, or elaborately prepared, as food.

    a plain diet.

13. flat or level.

    plain country.

    Antonyms:

    hilly

14. unobstructed, clear, or open, as ground, a space, etc.

15. Cards. being other than a face card or a trump.

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adverb

1. clearly and simply.

   He's just plain stupid.

noun

1. an area of land not significantly higher than adjacent areas and with relatively minor differences in elevation, commonly less than 500 feet (150 meters), within the area.

2. The Plains. Great Plains.

idioms

1. in plain sight. in plain sight.

plain ² American  

[pleyn] / pleɪn /

verb (used without object)

British Dialect.

1. to complain.

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plain ¹ British  

/ pleɪn /

adjective

1. flat or smooth; level

2. not complicated; clear

   the plain truth

3. not difficult; simple or easy

   a plain task

4. honest or straightforward

5. lowly, esp in social rank or education

6. without adornment or show

   a plain coat

7. (of fabric) without pattern or of simple untwilled weave

8. not attractive

9. not mixed; simple

   plain vodka

10. knitting of or done in plain

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noun

1. a level or almost level tract of country, esp an extensive treeless region

2. a simple stitch in knitting made by putting the right needle into a loop on the left needle, passing the wool round the right needle, and pulling it through the loop, thus forming a new loop

3. 1. the unmarked white ball, as distinguished from the spot balls

   2. the player using this ball

4. (in Ireland) short for plain porter, a light porter

   two pints of plain, please

adverb

1. (intensifier)

   just plain tired

plain ² British  

/ pleɪn /

verb

1. a dialect or poetic word for complain

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plain Scientific  

/ plān /

1. An extensive, relatively level area of land. Plains are present on all continents except Antarctica and are most often located in the interior regions. Because they can occur at almost any altitude or latitude, plains can be humid and forested, semiarid and grass-covered, or arid.

2. A broad, level expanse, such as an area of the sea floor or a lunar mare.

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plain More Idioms  

More idioms and phrases containing plain

• in plain English

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Related Words

See homely.

Other Word Forms

• plainly adverb
• plainness noun

Etymology

Origin of plain¹

First recorded in 1300–50; Middle English adjective, adverb, and noun plain(e), plein(e), from Old French adjective and noun plain(e), pleine, from Latin plānus “flat, level,” plānum “flat country”

Origin of plain²

First recorded in 1250–1300; Middle English plei(g)nen, plene(n), from Anglo-French plainer, pleiner, Old French plaign-, stem of plaindre, pleindre, from Latin plangere “to strike, beat (the breast, etc.), lament”

Explanation

Plain things are simple, unadorned, and even a little boring. Being a plain talker means you don't use pretentious, fancy words. But having a plain face means you're not much to look at. Plain comes from the Latin word planum, meaning "level ground." That's one meaning of the word, as in a flat prairie or low lying coastal flood plain. If something is in plain view, it's out in the open with no obstructions. But usually we use plain as an adjective to describe unembellished, bare, or unimpressive things. A white room with just an old bed and a chair is pretty plain.

Example Sentences

The Hartford fund also benefits from diversification, with exposure that goes beyond plain vanilla U.S.

From Barron's • Apr. 9, 2026

Trading oil at present is no plain sailing because transiting a tanker through the Strait of Hormuz is no plain sailing, either.

From MarketWatch • Apr. 9, 2026

It offers the customary plain benches inside, but other interior features, like an iron stove, sit outside.

From The Wall Street Journal • Apr. 4, 2026

The one advantage was that the dancers, mainly on a plain stage, could shine in a town that knows its dance.

From Los Angeles Times • Apr. 3, 2026

“But the letters came in plain white envelopes,” Jonah said.

From "Found" by Margaret Peterson Haddix

Related Words

• expanse
• field
• grassland
• meadow
• plateau
• prairie
• steppe