dead·head /ˈdɛdˌhɛd/
  免票的人;空車;無能力者,庸人
  Dead·head n.
  1. One who receives free tickets for theaters, public conveyances, etc. [Colloq. U. S.]
  2. Naut. A buoy. See under Dead, a.
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  deadhead
       n 1: a nonenterprising person who is not paying his way; "the
            deadheads on the payroll should be eased out as fast as
            possible"
       2: a train or bus or taxi traveling empty