팬(paen)
A person who likes and supports someone or something, especially celebrities or sports teams
When to use
Supporting celebrities, Cheering sports teams, Hobby enthusiasm
The nuance
팬 is used to express positive feelings and support. It fits when someone is passionate and loyal toward the liked subject.
안티(an-ti, anti)
A person who holds negative feelings toward someone or something and criticizes or opposes them
When to use
Criticizing celebrities, Forming negative public opinion, Opposing rival teams
The nuance
안티 is used to express dislike or opposition. It is the opposite of 팬 and fits when criticizing or disliking the subject.