noun (n)

• one who trains or exhibits animals(noun.person)

  Synonym:
  animal trainer
  

  source: wordnet30
• an agent who handles something or someone(noun.person)

  Example:
  The senator's campaign handlers.
  

  source: wordnet30
• (sports) someone in charge of training an athlete or a team(noun.person)

  Synonym:
  coach, manager
  

  source: wordnet30