Words That Rhyme With "Plainness" :
2 syllables:
faintness, fineness, gameness, goneness, grainedness, greenness, meanness, oneness, proneness, quaintness, sameness, saneness, strainedness, strangeness, tameness, thinness
3 syllables:
foregoneness, germaneness, ingrainedness, insaneness, jejuneness, sereneness, urbaneness