Game on horseback (4)
I believe the answer is:
polo
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">game on horseback</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for polo that I've seen before include "Game played in chukkas" , "jersey" , "A mint on horseback?" , "Equestrian game" , "Ball game played on horseback" .)