Adjective. To be loved by a few thousand fangirls despite being an ass; to have a homosexual kiss onstage, in a homophobic country and survive; to be good at doing impressions; to be painfully beautiful despite being male; to be a cat lady; to criticize a few hundred people in under ten seconds and be declared charming.
Kangin: What? You kissed a guy? You're such a heechul.
Siwon: You don't believe in God? That's crazy! Are you heechul?
Leeteuk: How can you get away with all of that stuff? That's not normal, you heechul!