The phrase "good dancer" means someone who moves their body gracefully and rhythmically while dancing.
Sentences with «good dancer»
Even if you are not a particularly good dancer you can have a fun date. (my-dating-advice.com)
My husband doesn't think I'm a very good dancer though... bahahaha! (stillbeingmolly.com)
A paper that purports to show that symmetrical bodies make for better dancers is finally retracted years after one of its authors identified fraud (sciencemag.org)