The Collaborative International Dictionary of English v.0.48:

Troop \Troop\, v. i. [imp. & p. p. Trooped; p. pr. & vb. n.
   Trooping.]
   1. To move in numbers; to come or gather in crowds or troops.
      "Armies . . . troop to their standard." --Milton.
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   2. To march on; to go forward in haste.
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            Nor do I, as an enemy to peace,
            Troop in the throngs of military men. --Shak.
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