English to English

noun (n)

• a soiled or discolored appearance(noun.attribute)

  Synonym:
  discolouration, stain
  

  source: wordnet30
• the act of changing the natural color of something by making it duller or dingier or unnatural or faded(noun.act)

  Synonym:
  discolouration
  

  source: wordnet30
• The act of discoloring, or the state of being discolored; alteration of hue or appearance.(noun)

  source: webster1913