Meaning of PLAIN in English
[plain] vi [ME, fr. OF plaindre, fr. L plangere to lament--more at plaint] (14c) archaic: complain
plain n [ME, fr. OF, fr. L planum, fr. neut. of planus flat, plain--more at floor] (14c) 1 a: an extensive area of level or rolling treeless country b: a broad unbroken expanse
2: something free from artifice, ornament, or extraneous matter plain adj (14c) 1 archaic: even, level
2: lacking ornament: undecorated
3: free of extraneous matter: pure
4: free of impediments to view: unobstructed
5. a (1): evident to the mind or senses: obvious "it's perfectly ~ that they will resist" (2): clear "let me make my meaning ~" b: marked by outspoken candor: free from duplicity or subtlety: blunt "~ talk"
6. a: belonging to the great mass of humans b: lacking special distinction or affectation: ordinary 7: characterized by simplicity: not complicated "~ home-cooked meals" 8: lacking beauty or ugliness syn see common, evident, frank -- plain.ly adv -- plain.ness n plain adv (14c): in a plain manner "saw them clearly and told you ~ --Amer. Documentation" plain adv [partly fr. ME plein entire, complete, fr. MF, full, fr. L plenus; partly fr. plain--more at full] (1535): absolutely "it ~ galled me to pay fancy prices --F. R. Buckley"
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012