Formal:
* Equestrienne: This is a classic, elegant term, often used in formal settings.
* Horsewoman: This is a more common and straightforward term, implying skill and experience.
* Rider: This is the most generic term, applicable to both men and women.
Informal:
* Girl rider: This is a simple and direct term.
* Horse girl: This term is often used affectionately, but can also have connotations of being obsessed with horses.
* Cowgirl: This term is typically associated with rodeo or Western riding.
More Specific:
* Jockey: This term is specific to racehorse riders, typically in professional settings.
* Show jumper: This term refers to a rider who competes in show jumping.
* Dressage rider: This term refers to a rider who specializes in dressage.
Ultimately, the best term to use will depend on the specific situation and the tone you want to convey.