noun (n)

• someone who gossips indiscreetly(noun.person)

  Synonym:
  blabbermouth, talebearer, tattler, tattletale, telltale
  

  source: wordnet30
• One who tells tales or stories, especially in a mischievous or officious manner; a talebearer; a telltale; a tattler.(noun)

  source: webster1913