(a) person who dances 跳舞的人
*He's a good dancer. 他跳舞跳得好.
(b) person who dances for payment 舞蹈演员
*She's a (tap-/ballet) dancer. 她是（踢踏舞[芭蕾舞]）舞蹈演员.
someone who dances as a profession
The dancer's technique is strong.
ballet/ballroom/flamenco etc dancer
Margot Fonteyn, the famous British ballet dancer
someone who dances
the dancers on the floor
Dave's a good dancer.
1. The dancer was adorned with flowers. 跳舞的人戴著很多花.
2. He is a clever dancer. 他是灵巧的舞蹈演员。
3. He is a dancer with perfect timing. 他是一个节拍准确的跳舞者.