Jumpers is fast and clean. Whoever gets around the course with the fastest time and no time faults wins. Hunters is very steady, slower, even paced. Its judged on the horses efforts and how well the horse responds. Most hunter rounds are slow. And people dont rush
Showjumping and jumpers are the same thing (that's what I learned). The difference between jumper and hunter is how the scoring works. Hunter is judged on manners, how the horse moves, conformation, and more on how the horse and rider looks. Jumper is judged based on how fast the horse and rider can finish the course with the least faults. That's the main difference between them. There are different rules for each discipline so this isn't exact but I hope it helped anyway!
Showjumping is based on how quick a rider and horse can jump a course and leave all the jumps up. The winning team is the team with the least faults (accumulated by knocking rails or going over the time limit) and the quickest time. Hunter jumper is scored on how effortless the round looked. The round flow, all jumps be the same, you must get your lead changes, and maintaining a consistant pace is important. Hunter judges typically like hunter horses that have a good jump and tuck their knees up, as well as having a pleasant expression the whole time.