The training of a horse in manoeuvres (8)
I believe the answer is:
dressage
'the training of a horse in manoeuvres' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for dressage that I've seen before include "Olympic event" , "equestrian routine" , "Method of horse training" , "Equestrian discipline" , "Event for rider" .)