Dispute case from Oxford with detective (4)
I believe the answer is:
odds
'dispute' is the definition.
(I've seen this before)
'case from oxford with detective' is the wordplay.
'case from' suggests removing the centre (the case or outside of the word).
'with' means one lot of letters go next to another.
'detective' becomes 'DS' (detective sergeant).
'oxford' with its middle removed is 'od'.
'od'+'ds'='ODDS'
(Other definitions for odds that I've seen before include "Betting ratio" , "Betting rates" , "Chance" , "The likelihood of something occurring rather than not" , "prices" .)