Bellicosity (noun)

1. A disposition or tendency towards aggression or war; a belligerent attitude.
2. An inclination to start fights or conflicts; a hostile or aggressive behavior.

Origin:

The word "bellicosity" comes from the latin word "bellicus" meaning "warlike", which in turn is derived from "bellum" meaning "war". it was first recorded in english in the late 16th century.

Examples:

1. The bellicosity of the two countries' leaders had escalated the situation to the brink of war.
2. The nation's bellicosity was the main cause of the conflict.
3. His bellicosity made it impossible for him to work with his colleagues.
4. She had to deal with his bellicosity every day.
5. The aggressive bellicosity of the country's leader made it difficult for the other countries to negotiate with them.