A Korean bird, called Crow tit in English. There is a common idiom/ saying : "the crow tit will break it's legs
trying to walk like a stork". Other translations include try-hard and poser. Basically trying to be something that your not.
BTS refers to themselves as baepsae because they are not part of a big name
entertainment company and they are still becoming
international idol stars. They are proud to be baepsae.