adjective

1. not decorated or elaborate; simple or basic in character. "good plain food" синонимы: simple, ordinary, unadorned, undecorated, unembellished, unornamented, unpretentious, unostentatious, unfussy, homely, homespun, basic, modest, unsophisticated, penny plain, without frills, stark, severe, spartan, austere, chaste, bare, uncluttered, restrained, muted, unpatterned, patternless, everyday, workaday
2. having no pretensions; not remarkable or special. "a plain, honest man with no nonsense about him" синонимы: straightforward, unpretentious, simple, ordinary, average, unassuming, unaffected, honest-to-goodness, ingenuous, artless, guileless, sincere, cracker-barrel
3. easy to perceive or understand; clear. "the advantages were plain to see" синонимы: obvious, clear, crystal clear, as clear as crystal, evident, apparent, manifest, patent, visible, discernible, perceptible, perceivable, noticeable, detectable, recognizable, observable, unmistakable, transparent, palpable, distinct, pronounced, marked, striking, conspicuous, overt, self-evident, indisputable, as plain as a pikestaff, staring someone in the face, writ large, written all over someone, as plain as day, plain to see, beyond (a) doubt, beyond question, standing/sticking out a mile
4. (of a person) not beautiful or attractive (typically used of a woman). "a plain, round-faced woman" синонимы: unattractive, unprepossessing, as plain as a pikestaff, ugly, ill-favoured, unlovely, ordinary-looking, homely, not much to look at, fugly, no oil painting, huckery
5. sheer; simple (used for emphasis). "the main problem is just plain exhaustion" синонимы: sheer, pure, downright, out-and-out, unmitigated, rank, nothing other than
6. denoting or relating to a type of knitting stitch produced by putting the needle through the front of each stitch from left to right.

adverb

1. used for emphasis. "perhaps the youth was just plain stupid" синонимы: downright, utterly, absolutely, completely, totally, beyond, really, thoroughly, positively, profoundly, categorically, simply, incontrovertibly, unquestionably, undeniably, plumb
2. clearly or unequivocally. "I'm finished with you, I'll tell you plain "

noun

a large area of flat land with few trees. "the coastal plain" синонимы: grassland, flatland, lowland, pasture, meadowland, open country, prairie, savannah, steppe, tableland, tundra, pampas, campo, llano, vega, veld, pediplain, champaign