What does hacking mean in horse riding?
https://en.wikipedia.org/wiki/Hack_(horse)
Hack within the activity of equestrianism commonly refers to one of two things: as a verb, it describes the act of riding a horse for light exercise, and as a noun, it is a type of horse used for riding out at ordinary speeds over roads and trails.The term is sometimes used to describe certain types of exhibition or horse show classes where quality and good manners of the horse are particularly important.
Hacking can mean a few things within the horse world.
Going for a hack can mead a stress free gentle ride outside the ring/arena and not strenuous enough to break a sweat, galloping on a loose rein etc.
I am assuming you are referring to Hacking as in a horse show, by which the horses are judged based on his performance in the show ring (general rule of: 60% score on conformation and soundness, 40% score on manners, education and paces) therefor is basically a beauty contest, a “hack” is a “quality” animal. The judges will set out workouts performed individually to test obedience and training of the horse and give the rider the opportunity to show the quality of the horses conformation and movement whilst giving the impression of covering ground easily and fluently.
Hope this helps 🙂