/dɪˈfiːt/
[verb] To win against someone or something in a fight, competition, or contest, or to stop a plan or idea from succeeding.
To 'defeat' someone once literally meant to 'undo' them — to unmake everything they had built.
The word 'defeat' arrives in English during the 14th century, carried across the Channel by the tide of Old French that followed the Norman Conquest of 1066. Its immediate source is the Old French word 'desfait', the past participle of the verb 'desfaire', meaning 'to undo' or 'to destroy'. But to understand the word fully, we need to trace that Old French form back to its own building blocks.
Old French 'desfaire' was assembled from two parts: the prefix 'des-' (from Latin 'dis-'), which expressed the idea of reversal or undoing, and the verb 'faire', meaning 'to do' or 'to make'. That verb 'faire' came directly from Latin 'facere', also meaning 'to do' or 'to make'. So the chain runs cleanly: Latin 'dis-' + Latin 'facere' → Old French 'desfaire' → Old French 'desfait' → Middle English 'defeat'. To defeat someone was, at its roots, to un-make them, to reverse or undo whatever they had accomplished.
When the word first entered Middle English, it was used in a surprisingly broad and concrete way. You could 'defeat' a legal agreement by breaking or annulling it, or 'defeat' a building by tearing it down. The earliest English uses carried this strong sense of dismantling and destruction — not simply winning, but actively unravelling something. A military victory was just one version of this idea: to defeat an army was to dismantle its fighting power entirely.
Over the course of the 15th and 16th centuries, as England fought wars both abroad and at home, the military sense gradually pulled ahead and became the word's dominant meaning. Writers and soldiers found it a powerful term for the total collapse of an opposing force. By the time Shakespeare was writing, 'defeat' had settled comfortably into the vocabulary of battle and competition, while still occasionally surfacing in its older legal sense of cancelling or nullifying something.
Interestingly, the Latin root 'facere' is one of the most productive roots in the entire English language. Through Latin and Old French, it gave us a remarkable family of words: Latin 'facere' → Old French 'faire' → English 'feat'; Latin 'facere' → Old French 'forfaire' → English 'forfeit'; Latin 'facere' → Old French 'parfaire' → English 'perfect'; and Latin 'facere' directly into English as 'factor', 'factory', and 'manufacture'. Every time you admire a feat of skill, you are touching the same ancient root as defeat.
What makes 'defeat' so linguistically satisfying is that it still quietly carries its original meaning inside it. When a team is defeated in sport, something really has been undone — a strategy has been dismantled, a plan has been reversed, ambitions have been taken apart piece by piece. The modern word and the medieval one are, at their heart, saying exactly the same thing.