The Collaborative International Dictionary of English v.0.48:

Pettifog \Pet"ti*fog\, v. t.
   To advocate like a pettifogger; to argue trickily; as, to
   pettifog a claim. [Colloq.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pettifog \Pet"ti*fog\, v. i. [imp. & p. p. Pettifogged; p. pr.
   & vb. n. Pettifogging.] [Petty + fog to pettifog.]
   1. To do a petty business as a lawyer; also, to do law
      business in a petty or tricky way. "He takes no money, but
      pettifogs gratis." --S. Butler.
      [1913 Webster]

   2. To debate or quarrel over unimportant, trifling matters.
      [PJC]

   3. To use subterfuge, deception, or flattery for any purpose;
      to practice chicanery.
      [PJC]

WordNet (r) 3.0 (2006):

pettifog
    v 1: argue over petty things; "Let's not quibble over pennies"
         [syn: quibble, niggle, pettifog, bicker,
         squabble, brabble]

Moby Thesaurus II by Grady Ward, 1.0:

41 Moby Thesaurus words for "pettifog":
   argue, argufy, bandy words, bicker, carp, catch at straws, cavil,
   choplogic, contend, contest, cross swords, cut and thrust, cut up,
   discept, dispute, fault-find, find fault, give and take, hassle,
   have it out, join issue, lock horns, logomachize, moot, nitpick,
   pick holes, pick to pieces, plead, polemicize, polemize,
   pull apart, pull to pieces, quibble, spar, take exception,
   take sides, tear apart, tear to pieces, thrash out,
   try conclusions, wrangle