Explain in English
A dancer is someone who dances for fun, as a hobby, or for a job. The dancers at a rock concert often look like they're enjoying the music most of all.
You can be a dancer at your cousin's wedding reception, or a dancer in a professional ballet corps. Though the second example requires a much more serious commitment than the first, they both require you to move your body rhythmically, usually accompanied by music. In Old French, dancer means "to dance," and its origin is somewhat uncertain. One theory connects the word to the Old Frisian dintje, which means "tremble or quiver."