What is the "going?"

When a horseman uses the term going, he means the ground underneath his horse's hooves. Going refers to how wet the ground is, how smooth, everything that might help (or hinder) a horse in crossing it.

You might hear somebody say that a horse doesn't like the "going" - I once knew a horse that absolutely hated being ridden if it was particularly damp or muddy and he would let you know in no uncertain terms that he wasn't happy about it! In contrast, "hard" or "firm" going might make a horse more likely to be lame or be bothered by an old injury (and is definitely less fun if you fall off!).