War-horse is a term often used to describe a horse that is strong, brave, and has been trained for battle. However, there are a number of different synonyms that can be used to describe such a horse. For example, one could use the term "charger" to describe a horse that was bred specifically for battle. "Steed" is another synonym that can be used to describe a strong and powerful horse, while "destrier" is a term that was commonly used in medieval times to describe a horse that was specially trained for warfare. Other synonyms for war-horse might include "battle horse," "mounted warrior," or simply "war-mount." Ultimately, the term used will depend on the specific context and the tone that the writer is trying to convey.