The Collaborative International Dictionary of English v.0.48:

Quibbler \Quib"bler\, n.
   One who quibbles; a caviler; also, a punster.
   [1913 Webster]

WordNet (r) 3.0 (2006):

quibbler
    n 1: a disputant who quibbles; someone who raises annoying petty
         objections [syn: quibbler, caviller, caviler,
         pettifogger]

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "quibbler":
   belittler, captious critic, carper, caviler, censor, censurer,
   common scold, critic, criticizer, equivocator, faultfinder,
   frondeur, hairsplitter, hedger, momus, mystificator, mystifier,
   nitpicker, obscurantist, palterer, pettifogger, picayune critic,
   prevaricator, pussyfoot, pussyfooter, scold, shuffler, smellfungus,
   tergiversator