Thrash in the return game (4)
I believe the answer is:
flog
'thrash' is the definition.
(thesaurus)
'in the return game' is the wordplay.
'in the' becomes 'fl' (I can't explain this - if you can you should believe this answer much more).
'return' shows that the letters should be reversed in order.
'game' becomes 'go' (go is a kind of game).
'go' written backwards gives 'og'.
'fl'+'og'='FLOG'
Can you help me to learn more?
(Other definitions for flog that I've seen before include "Beat with a whip or rod" , "Beat with whip or slangily sell" , "Whip severely" , "Scourge, whip" , "Swing a cat, perhaps" .)