Source : Webster's Revised Unabridged Dictionary (1913)

Hairsplitting \Hair"split`ting\, a.
   Making excessively nice or trivial distinctions in reasoning;
   subtle. -- n. The act or practice of making trivial
   distinctions.

         The ancient hairsplitting technicalities of special
         pleading.                                --Charles
                                                  Sumner.

Source : WordNet®

hairsplitting
     adj : developed in excessively fine detail; "finespun
           distinctions" [syn: {finespun}]
     n : making too fine distinctions of little importance; "they
         didn't take his hairsplitting seriously" [syn: {word-splitting}]