Swagggg #BOYNEXTDOOR #보이넥스트도어 #BND #명재현 #JAEHYUN

In the Korean comments

One top comment argues that as Jaehyun has gained experience, he has developed his own 춤선 (chumseon, distinctive lines and flow of movement) and vibe. Another reads, in translation, “I was so busy watching Jaehyun’s dancing and looks that I only just noticed the glasses”—a detail to check on a second watch.

What the words mean

개고능 (gaegoneung) does not refer to a “dog.” Here 개 (gae-, forceful intensifier)- (gae-) is a forceful intensifier, while 고능 (goneung) is online shorthand for being highly capable; together, the top comment is calling Jaehyun “ridiculously skilled” in casual, emphatic fan slang.