Referee a right snappy sort? (7)
I believe the answer is:
arbiter
'referee' is the definition.
(I've seen this in another clue)
'a right snappy sort?' is the wordplay.
'a right' becomes 'ar' (I've seen this in other clues).
'snappy sort?' becomes 'biter' (I can't explain this - if you can you should believe this answer much more).
'ar'+'biter'='ARBITER'
Can you help me to learn more?
(Other definitions for arbiter that I've seen before include "One appointed to settle a dispute" , "Settler of dispute" , "One must exercise judgment" , "Mediator or referee" , "expert" .)