The Collaborative International Dictionary of English v.0.48:

Philadelphia lawyer \Philadelphia lawyer\
   A lawyer knowledgeable about the most detailed and minute
   points of law, especially one with an exceptional propensity
   and ability to exploit fine technical points of law for the
   client's advantage. [U. S.]
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Lawyer \Law"yer\, n. [From Law, like bowyer, fr. bow.]
   1. One versed in the laws, or a practitioner of law; one
      whose profession is to conduct lawsuits for clients, or to
      advise as to prosecution or defence of lawsuits, or as to
      legal rights and obligations in other matters. It is a
      general term, comprehending attorneys, counselors,
      solicitors, barristers, sergeants, and advocates.
      [1913 Webster]

   2. (Zool.)
      (a) The black-necked stilt. See Stilt.
      (b) The bowfin (Amia calva).
      (c) The burbot (Lota maculosa).
          [1913 Webster]

   Philadelphia lawyer, A lawyer knowledgeable about the most
      detailed and minute points of law, especially one with an
      exceptional propensity and ability to exploit fine
      technical points of law for the client's advantage.
      [PJC]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "Philadelphia lawyer":
   Artful Dodger, Yankee horse trader, ambulance chaser, apologist,
   arguer, argufier, casuist, charmer, controversialist,
   crafty rascal, debater, disceptator, disputant, dodger, fox,
   glib tongue, guardhouse lawyer, horse trader, logomacher,
   logomachist, mooter, pettifogger, pilpulist, polemic, polemicist,
   polemist, reynard, shyster, slick citizen, sly dog, slyboots,
   sweet talker, swindler, trickster, wrangler