athlete

Athlete comes from Latin āthlēta, from Ancient Greek ἀθλητής (athlētḗs), meaning one who competes for a prize. That noun traces back to the verb ἀθλέω (athléō, 'compete for a prize'), rooted in ἆθλον (âthlon, 'prize') or ἆθλος (âthlos, 'competition').

The word passed from Greek into Latin, then into Middle French and Middle English, keeping its core sense of a competitor throughout.