Other forms: belligerents
If someone is belligerent, they're eager to fight. It's a good idea to avoid hardcore hockey fans after their team loses — they tend to be belligerent.
Belligerent comes from the Latin word bellum, for "war." You can use it to talk about actual wars — the nations taking part in a war are called belligerents — but usually belligerent describes a psychological disposition. If you're running a school for aggressive boys, do plenty of arts and crafts to prevent them from becoming too belligerent. The stress is on the second syllable: bə-LIJ-ə-rənt.