from The American Heritage® Dictionary of the English Language, 4th Edition
- intransitive v. To be concerned with or find fault with insignificant details. See Synonyms at quibble.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- v. To correct minutiae or find fault in unimportant details; to kvetch.
- v. To pick nits - lice eggs - from someone’s hair.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- v. be overly critical; criticize minor details
From nit + pick, originally referring to literally removing invisibly-tiny louse eggs by hand. (Wiktionary)