Cowboy

[Rihanna]

A cattle herder; a drover; specifically, one of an
adventurous class of herders and drovers on the plains of the Western
and Southwestern United States.

[Britney]

(especially in the western US) a man who herds and tends cattle, performing much of his work on horseback.

[Lizzy Liz]

Cowboy in Cycling. A cyclist who rides erratically.

[Mark Zuckerberg]

A man, typically one on horseback, who herds and tends cattle, especially in the western US and as represented in westerns and novels.