Sack race reorganised to protect stunted bone (7)
I believe the answer is:
cashier
'sack' is the definition.
(I've seen this before)
'race reorganised to protect stunted bone' is the wordplay.
'reorganised' is an anagram indicator.
'to protect' means one lot of letters goes inside another (inserted letters are held or protected).
'stunted bone' becomes 'shi' (I am not sure about this - if you are sure you should believe this answer much more).
'race' with letters rearranged gives 'caer'.
'caer' placed around 'shi' is 'CASHIER'.
Can you help me to learn more?
(Other definitions for cashier that I've seen before include "banking officer" , "Employee who takes in or gives out money" , "Person dealing with money" , "employee accepting money" , "One handles the money" .)