/ˈbɛlɪkəʊs/
[adjective] Describing a person, group, or nation that is eager to argue, fight, or start a war. Someone who is bellicose is aggressive and often looks for conflict.
The same ancient root that gives us 'bellicose' also hides inside 'duel' — both words trace back to the Latin word for war.
At the heart of 'bellicose' lies the Latin noun 'bellum', meaning war. The Romans used 'bellum' constantly — it appeared in their laws, their poetry, and their history books — and from it they built the adjective 'bellicosus', meaning warlike, aggressive, or fond of fighting. This adjective passed into English in the fifteenth century, keeping its original shape almost perfectly intact, as if the word itself refused to surrender any ground along the way.
The Latin root 'bellum' is far older than Rome itself. Scholars believe it descended from an even earlier Proto-Italic form, 'duellum', which meant a fight or contest between two parties. You can still see that ancient ancestor hiding inside the English word 'duel' — a fight between two people — which came to English via Latin 'duellum' → Italian 'duello' → English 'duel'. Over centuries of spoken Latin, 'duellum' softened and shifted until the opening 'du-' collapsed into the simpler 'b-', giving Romans their familiar 'bellum'. The same transformation left its fingerprints across the Latin language.
From 'bellum', Latin built a whole family of war-related words. 'Bellator' meant a warrior, and 'rebellare' meant to make war again — to fight back. That verb travelled through Old French as 'rebeller' before arriving in English as 'rebel'. Similarly, 'antebellum' — from Latin 'ante' meaning before, plus 'bellum' — gives us the term still used to describe the American South before the Civil War. Each of these words carries the same ancient heartbeat of conflict inside it.
When 'bellicose' entered English in the 1400s, it was largely a word of formal writing — the kind found in chronicles, political essays, and translations of classical texts. At first it described entire nations or armies. A bellicose people was one that lived for conquest. Over time, however, the word broadened, and by the eighteenth and nineteenth centuries it was routinely applied to individual people — a bellicose neighbour, a bellicose politician — anyone with an aggressive, combative personality and a hunger for argument or confrontation.
What makes 'bellicose' interesting today is that it sits at an elegant distance from its cruder synonyms. To call someone 'aggressive' or 'violent' is direct and blunt. But 'bellicose' carries a slightly formal, almost literary weight — it suggests not just anger, but a readiness to escalate, a strategic love of conflict. Writers and journalists often choose it precisely because it implies calculation alongside hostility. In modern political commentary, a 'bellicose' speech or a 'bellicose' foreign policy hints at the machinery of war, not just a hot temper.