Game with mallets (4)
I believe the answer is:
polo
'game with mallets' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for polo that I've seen before include "Oriental visitor < ? Sucker having a hole" , "Horsey ball game" , "Horseback sport" , "Game played on horseback wielding mallets" , "Game played on horses or in water" .)