The most common and most likely answer to this crossword clue is the 8 letter word PEDANTRY
I've seen this crossword clue in The Sunday Telegraph
P
E
D
A
N
T
R
Y
More clues leading to the result PEDANTRY
- Fastidiousness comes from editor stuck in room
- Nit-picking editor entering kitchen store
- Nit-picking fellow going into favourite lines
- Still room to absorb education that’s hair-splitting
- Nit-picking editor brought in to criticise essay
- Nit-picking journalist taken in by wheeze on railway
- Finding fault with shortened Christmas show featuring Sheeran track
- . Stillroom for education to be incorporated in this
- Show of erudition Ed included in harsh review and essay
- Nit-picking journo in grocery store?
Buddy explains!

The straight part
We know that "Nit-picking" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case nit-picking = pedantry.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PEDANTRY mean?
PEDANTRY noun- An excessive attention to detail or rules.
- An overly ambitious display of learning.