New word: "belligerent"

bel·lig·er·ent

/bəˈlijərənt/
adjective

  • hostile and aggressive.
    "a bull-necked, belligerent old man"

noun

  • A nation or person engaged in war or conflict, as recognized by international law.

As you can imagine, this word was used a lot in my current book on World War II.