1. A horse that has not been trained or ridden: This is the most common understanding of the term. An unbroken horse is one that is wild or has never been domesticated and trained to accept a rider. These horses are often unpredictable and can be dangerous.
2. A horse that has been broken but has not been ridden extensively: This could be a young horse that has just started training or an older horse that has had a long break from riding. These horses may still be hesitant or nervous about being ridden.
3. A horse that is strong and resilient: This is a more metaphorical meaning, often used to describe a person who is strong and able to overcome challenges.
4. A specific breed of horse: There is no recognized breed of horse called "unbroken horse".
To clarify what you mean by "unbroken horse", please provide more context. For example, are you asking about:
* The characteristics of an unbroken horse?
* How to train an unbroken horse?
* The dangers of riding an unbroken horse?
Once you provide more information, I can give you a more specific and helpful answer.