The Collaborative International Dictionary of English v.0.48:

Robber \Rob"ber\, n.
   One who robs; in law, one who feloniously takes goods or
   money from the person of another by violence or by putting
   him in fear.
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         Some roving robber calling to his fellows. --Milton.
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   Syn: Thief; depredator; despoiler; plunderer; pillager;
        rifler; brigang; freebooter; pirate. See Thief.
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   Robber crab. (Zool.)
   (a) A purse crab.
   (b) Any hermit crab.

   Robber fly. (Zool.) Same as Hornet fly, under Hornet.


   Robber gull (Zool.), a jager gull.
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