The most common and most likely answer to this crossword clue is the 6 letter word PEDANT
I've seen this crossword clue in The Guardian
P
E
D
A
N
T
More clues leading to the result PEDANT
- Particular person in prison will be visited by US lawyer
- Stickler enraged and in bad mood
- Particular person long enthralling editor
- Person who’s picky, upset and in a bad mood
- Nit-picker removing end of chain from necklace
- One picking nits from pet and dancing
- Old teacher favoured pupil circumventing grade of proficiency
- Stickler for the rules gasped following editor’s promotion
- Quibbler longed to displace editor
- Stopped Anthony arresting quibbler
Buddy explains!

The straight part
We know that "One picking nits" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one picking nits = pedant.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 PEDANT mean?
PEDANT noun- A teacher or schoolmaster.
- A person who emphasizes their knowledge through strict adherence to rules of vocabulary and grammar.
- A person who is overly concerned with formal rules and trivial points of learning.
- Pedantic.