hair-splitter

His method of reasoning was very popular in the schools during the Middle Ages, and a very skillful hair-splitter was called a Dunse; but at last, through the influence of the antagonists of the philosopher, the word passed into a term of reproach.

Evidently, coroner and doctor were inclined to be testy with each other, and the newspaper report left the impression that Dr. Scaife was a hair-splitter.

Over the last decade, he's made a hair-splitter's tour of academic conferences, telling his colleagues that Black-6 mice are different from 129s, that mice are different from rats, that males are different from females, and that rodents are different from humans.

Jeff Mogil is a hair-splitter.

He isn't going to be the dead easy mark I hoped to find in the son of the old bankrupt hair-splitter, Genie, girl.