verb (v)

• make or become black(verb.change)

  Example:
  The smoke blackened the ceiling.
  The ceiling blackened.
  

  Synonym:
  black, melanise, melanize, nigrify
  Antonym:
  white, whiten
  

  source: wordnet30
• burn slightly and superficially so as to affect color(verb.change)

  Example:
  The cook blackened the chicken breast.
  

  Synonym:
  char, scorch, sear
  

  source: wordnet30
• To make or render black.(verb)

  source: webster1913
• To grow black or dark.(verb)

  source: webster1913