IPA: /ˌbɛlɪˈkɒsɪti/
KK: /bɛlɪˈkɑsɪti/
A tendency to be aggressive or ready to fight.
His bellicosity made it difficult for him to maintain friendships.
Bellicosity is formed from "bellum" (meaning war) and the suffix "-osity" (meaning quality or state of). The word describes the quality or state of being inclined to fight or engage in war.
Think of 'bellum' which means war, and '-osity' indicating a quality. This helps you remember that bellicosity refers to a tendency towards warlike behavior.
No commonly confused words.