What does Bomb-proof horse mean?

Bomb-proof horse meaning in Urban Dictionary

A horse that's well trained and peaceful, that's not effortlessly spooked. Term originated for armed forces horses which should be "bomb-proof" so they never spook on sound of a bomb/gun/etc.kid's operating ponies frequently should be bomb-proof because kids will run and jump and make loud noises--all things that might scare a regular horse and cause him to hurt a person.