Hairsplitter (6)
I believe the answer is:
'hairsplitter' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for pedant that I've seen before include "Stickler for trifles" , "Person who is strict on rules and details" , "One is over-concerned with detail" , "One particular" , "Unimaginative person who insists on petty rules" .)