noun (n)

• someone who listens attentively(noun.person)

  Synonym:
  attender, hearer, listener
  

  source: wordnet30
• a student who attends a course but does not take it for credit(noun.person)

  source: wordnet30
• a qualified accountant who inspects the accounting records and practices of a business or other organization(noun.person)

  source: wordnet30
• A hearer or listener.(noun)

  source: webster1913