What term describes someone who is inclined or eager to fight and is often hostile?

The term that describes someone who is inclined or eager to fight and is often hostile is "belligerent." This word originates from the Latin 'bellum,' meaning war, and is typically used to characterize aggressive behavior or attitudes. A belligerent person tends to initiate conflict or respond to situations with hostility, showcasing a readiness to engage in a fight or argument.

In contrast, the other terms do not encapsulate this combative nature as effectively. "Brash" refers to someone who is bold or overconfident, often in a reckless way, but does not specifically relate to a desire for conflict. "Benign" describes someone who is gentle and kindly, completely opposite to the concept of hostility. "Cantankerous" denotes someone who is bad-tempered and argumentative, but this term does not necessarily imply a readiness to fight in the same way that belligerent does. Hence, belligerent is the most accurate descriptor in the context provided.