'vigour' originates from Latin, specifically the word 'vigor', where the root 'vigere' meant 'to be lively or to be strong'.

'vigour' changed from Latin 'vigor' through Old French/Anglo-French 'vigor' and Middle English 'vigour', and eventually became the modern English word 'vigour'. The simplified US spelling 'vigor' developed later.

Initially it meant 'liveliness' or 'active strength'; over time it retained this core sense while extending to the intensity or force of action or expression.