What is "nitpickers"

Usage examples of "nitpickers".

That some nitpickers in the bureaucracy wouldn’t have seen your discovery as a possible tool to be explored.

After standing the yapping of nitpickers all the day—" Viri dovix stared at Gorgidas until the doctor, reddening, urged him on with a rude gesture "—what better way to ease the sorrows than with sweet wine?

All of which meant he wished the whiners and nitpickers would get the hell out of his way so he could get on with enjoying all the marvelous new features the change in design philosophy had brought with it.