speculator
  投機者,投機商人,思索者
  Spec·u·la·tor n.  One who speculates. Specifically: (a) An observer; a contemplator; hence, a spy; a watcher. [Obs.]
  (b) One who forms theories; a theorist.
     A speculator who had dared to affirm that the human soul is by nature mortal.   --Macaulay.
  (c) Com. One who engages in speculation; one who buys and sells goods, land, etc., with the expectation of deriving profit from fluctuations in price.
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  speculator
       n 1: someone who makes conjectures without knowing the facts
       2: someone who risks losses for the possibility of considerable
          gains [syn: plunger]