'pursuer' originates from Old French, specifically the word 'poursuivre' (to pursue), ultimately from Latin 'prosequi', where 'pro-' meant 'forward' and 'sequi' meant 'to follow'.

'prosequi' (Latin) changed into Old French 'poursuivre', then into Middle English forms such as 'pursuen'/'pursuen' and later became the modern English verb 'pursue' and the agent noun 'pursuer'.

Initially it meant 'to follow forward' (literally 'to follow after'), but over time it evolved into its current uses meaning 'to chase' or 'to strive to obtain/achieve' (and 'pursuer' as 'one who chases or seeks').