Fellow gets snappy about including extremely detailed exact reference (7,3,5)
I believe the answer is:
chapter and verse
'exact reference' is the definition.
'fellow gets snappy about including extremely detailed' is the wordplay.
I cannot really see how this works, but
'fellow' could be 'chap' (synonyms) and 'chap' is found in the answer.
'about' could be 'a' (abbreviation in Chambers) and 'a' is present in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for chapter and verse that I've seen before include "precise testimony" , "location of Biblical text" , "Full" , "in detail" , "authority" .)