From the Latin root bell-, which means war, we get bellicose. Someone who is bellicose is warlike, and inclined to quarrel. The word is similar to belligerent, which also employs the bell- root.
A person who is truculent has a fierce, savage nature.
As I drive a smaller car, I often find trucks—from the 18-wheeler to the 4×4—to be quite truck-ulent when they drive. A silly mnemonic, but next time you are cut off by a truck, instead of giving the proverbial middle-finger, you can just mutter, what a truculent fellow.
Pugnacious means having an inclination to fight and be combative. A useful mnemonic is a pug dog—you know, those really small dogs that always try to attack you while releasing a fusillade of yaps.
If you are contentious, you like to fight with words. If you know somebody who is always trying to pick an argument about something, no matter how trivial, that person is contentious.
Jingoism is bellicosity meets patriotism. A person who thinks their country should always be at war is a jingoist. The word is similar to hawkish, a word that means favoring conflict over compromise.
In the days leading up to war, a nation typically breaks up into the two opposing camps: doves, who do their best to avoid war, and jingoists, who are only too eager to wave national flags from their vehicles and vehemently denounce those who do not do the same.