Formal:
* Terpsichorean: This word comes from the Greek muse of dance, Terpsichore, and is a more formal and poetic way to describe a good dancer.
* Ballroom dancer: This term implies a high level of skill and grace in ballroom dances.
* Professional dancer: This clearly states the person's occupation and suggests a high level of skill.
Informal:
* Dancing star: This is a more informal way to describe a good dancer, often used in a playful or celebratory way.
* Whirlwind: This describes a dancer who moves with great energy and speed.
* Graceful dancer: This emphasizes the elegance and beauty of the dancer's movements.
You could also use an adjective:
* Skilled dancer: This directly emphasizes the dancer's ability.
* Talented dancer: This highlights the natural aptitude for dance.
The best choice will depend on the specific context and desired tone.