What's the noun for hairsplitting? Here's the word you're looking for.
hairsplitter
A person who makes extremely, possibly excessively, finedistinctions (who would separate something as fine as a hair into two pieces and distinguish them).
“Despite the productive discussion that was taking place, the hairsplitting among the team members prevented any meaningful progress towards a solution.”
“The mass of the party, he said, did not trouble their heads about theories, but plodded along unmindful of hairsplitting.”
“It was fine legal reasoning, not without some of that hairsplitting for which Jefferson reproached Randolph.”
