Bareback (adjective)

1. Without a saddle or other covering on the back of an animal.
2. Without a protective covering or safety device.

Origin:

From bare back, meaning riding a horse or other animal without a saddle.

Examples:

1. He rode the horse bareback.
2. Bareback riding is a popular sport in rodeos.
3. She went bungee jumping bareback.
4. The daredevil rode the motorcycle bareback through the loop.
5. The cowboy won the rodeo event bareback riding.