1. Meaning: Successful Fan. Usually it’s used for fans who meet their favorite artist or even ones who became an artist themselves!
  2. Example:
  3. A: I heard IU is a huge Seongdoeg! She was a big fan of Taeyang (BigBang)
  4. B: What? really? sure she is 🙂
  5. Etymology: Seong gong han deog hu (성공한 덕후)