The Collaborative International Dictionary of English v.0.48:

Prowl \Prowl\, v. t. [imp. & p. p. Prowled; p. pr. & vb. n.
   Prowling.] [OE. prollen to search about; of uncertain
   origin, perh. for proglen, a dim. of prog to beg, or proke to
   poke. Cf. Proke.]
   1. To rove over, through, or about in a stealthy manner;
      esp., to search in, as for prey or booty.
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            He prowls each place, still in new colors decked. --
                                                  Sir P. Sidney.
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   2. To collect by plunder; as, to prowl money. [Obs.]
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