Equestrian discipline (8)
I believe the answer is:
dressage
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">equestrian discipline</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for dressage that I've seen before include "The training of a horse in manoeuvres" , "equestrian activity" , "Red gases (anag)" , "Part of equestrian event" , "Olympic event" .)