The Collaborative International Dictionary of English v.0.48:

Rover \Rov"er\, n. [D. roover a robber. See Rove, v. i.]
   1. One who practices robbery on the seas; a pirate.
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            Yet Pompey the Great deserveth honor more justly for
            scouring the seas, and taking from the rovers 846
            sail of ships.                        --Holland.
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   2. One who wanders about by sea or land; a wanderer; a
      rambler.
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   3. Hence, a fickle, inconstant person.
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   4. (Croquet) A ball which has passed through all the hoops
      and would go out if it hit the stake but is continued in
      play; also, the player of such a ball.
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   5. (Archery)
      (a) Casual marks at uncertain distances. --Encyc. Brit.
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      (b) A sort of arrow. [Obs.]
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                All sorts, flights, rovers, and butt shafts.
                                                  --B. Jonson.
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   At rovers, at casual marks; hence, at random; as, shooting
      at rovers. See def. 5
      (a) above. --Addison.
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                Bound down on every side with many bands because
                it shall not run at rovers.       --Robynson
                                                  (More's
                                                  Utopia).
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