An athlete (American and British English) or sportsperson, sportsman or sportswoman (British English) is a person who competes in one or more sports that involve physical strength, speed and/or endurance. Athletes may be professionals or amateurs.[1]

Most professional athletes have particularly well-developed physiques obtained by extensive physical training and strict exercise accompanied by a strict dietary regimen.

The word "athlete" is a romanization of the Greek: άθλητὴς, athlētēs, one who participates in a contest; from ἄθλος, áthlos, or ἄθλον, áthlon, a contest or feat. It is the general term for all participants in any physical sport; its application to those who participate in other activities, such as horse riding or driving, is somewhat controversial.

So it's extremely subjective.