noun (n)

• a theatrical performer(noun.person)

  Synonym:
  histrion, player, role player, thespian
  

  source: wordnet30
• a person who acts and gets things done(noun.person)

  Example:
  He's a principal actor in this affair.
  

  Synonym:
  doer, worker
  

  source: wordnet30
• One who acts, or takes part in any affair; a doer.(noun)

  source: webster1913