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Synonyms for Plain (same or very similar meaning)

WordNet sense 1 (extensive tract of level open land):
field, champaign

WordNet sense 2 (a basic knitting stitch):
knit, knit stitch, plain stitch

WordNet sense 3 (not mixed with extraneous elements):
sheer, unmixed, unmingled

WordNet sense 4 (free of extraneous elements of any kind):

WordNet sense 5 (severely simple in line or design):

WordNet sense 6 (unornamented):

WordNet sense 7 (plain and unpretentious):

WordNet sense 8 (having no adornment or coloration):

WordNet sense 9 (apart from anything else; without additions or modifications):
bare, mere

WordNet sense 10 (severely simple):
severe, stark, austere

WordNet sense 11 (lacking patterns especially in color):

WordNet sense 12 (clearly revealed to the mind or the senses or judgment):
apparent, evident, manifest, patent, unmistakable, patent

WordNet sense 13 (easily perceived by the senses or grasped by the mind):

WordNet sense 14 (express complaints, discontent, displeasure, or unhappiness):
complain, kick, kvetch, quetch, sound off

WordNet sense 15 (free from any effort to soften to disguise):

WordNet sense 16 (extended senses; direct in means or manner or behavior or language or action):

WordNet sense 17 (lacking embellishment or ornamentation):
spare, unembellished, unornamented

WordNet sense 18 (not decorated with something to increase its beauty or distinction):
unadorned, undecorated

WordNet sense 19 (unmistakably (`plain' is often used informally for `plainly')):
apparently, evidently, manifestly, obviously, patently, plainly

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