noun (n)

• a decrease in price or value(noun.act)

  Example:
  Depreciation of the dollar against the yen.
  

  Antonym:
  appreciation
  

  source: wordnet30
• decrease in value of an asset due to obsolescence or use(noun.possession)

  Synonym:
  wear and tear
  

  source: wordnet30
• a communication that belittles somebody or something(noun.communication)

  Synonym:
  derogation, disparagement
  

  source: wordnet30
• The act of lessening, or seeking to lessen, price, value, or reputation.(noun)

  source: webster1913