Dispute overturned criminal charges (4)
I believe the answer is:
spar
'dispute' is the definition.
(I've seen this before)
'overturned criminal charges' is the wordplay.
'overturned' shows that the letters should be reversed in order.
'criminal charges' becomes 'raps' (as in 'to take the rap').
'raps' reversed gives 'SPAR'.
(Other definitions for spar that I've seen before include "What boxers do" , "Box - girder" , "A mineral; nautical pole" , "Box in training - nautical pole" , "Box (lightly) - fight (verbally)" .)