Synonyms for Pettifogger (same or very similar meaning)
WordNet sense 1 (a person (especially a lawyer or politician) who uses unscrupulous or unethical methods):
shysterWordNet sense 2 (a disputant who quibbles; someone who raises annoying petty objections):
caviler, quibbler, cavillerFrom the ODE community, based on WordNetadd/edit