A person who actively participates in physical sports, especially with great skill; a sportsperson.
An exceptionally physically fit person.
A participant in a group of sporting activities which includes track and field, road running, cross country running and racewalking.
She's the first athlete in her sport to obtain a corporate sponsor.
One who challenges; especially, one who plays against the current champion of a game or contest in hopes of winning and becoming the new champion.