do·er /ˈduɚ/
  行為者,實幹家
  Do·er n.
  1. One who does; one who performs or executes; one who is wont and ready to act; an actor; an agent.
     The doers of the law shall be justified.   -- Rom. ii. 13.
  2. Scots Law An agent or attorney; a factor.
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  doer
       n : a person who acts and gets things done; "he's a principal
           actor in this affair"; "when you want something done get
           a doer"; "he's a miracle worker" [syn: actor, worker]