Bwelk is a Korean slang popularized in the internet by mocking Moon Hee Jun's gothic voice of "break" in his song I.

Usage

뷁 is not a letter found in standard Korean, nonetheless it has found its place in the online South Korean community. The neologism is used to express disgust in an intentionally elementary manner while subtly avoiding the connotations carried by words deemed profane by the general public. In many contexts, the word also implies empathy or sympathy for those in similar negative situations.

John Doe: I have so much work to do this week!<br />
Jane Doe: Bwelk

The above is a possible, but somewhat unnatural example of how bwelk may be used. In addition to its usage as a simple expression for disgust, bwelk is also used as an adverb. '뷁적이게' in broken English roughly translates into 'bwelkily'. "The technician bwelkily attempted to fix the machines" is again, a slightly out of mainstream but possible way in which bwelk may be used.