Back sport involving driving belt (4)
I believe the answer is:
flog
'belt' is the definition.
(thesaurus)
'back sport involving driving' is the wordplay.
'back' shows that the letters should be reversed in order.
'sport involving driving' becomes 'golf' (a golfer drives a ball from a tee).
'golf' written backwards gives 'FLOG'.
(Other definitions for flog that I've seen before include "Whip severely" , "Lash" , "Beat with a whip or rod" , "Exchange for money" , "Swing a cat, perhaps" .)