what is the meaning of hyung-nim?
형님 (hyung-nim / hyeong-nim) is a Korean word that means “respected older brother”.
형 (hyung / hyeong) is “older brother”, addressed by a younger male to an older male (they don’t have to be actual brothers, though). The 님 (nim) suffix is an honorific, which shows great respect towards the addressee. (It can only be applied to certain nouns, though.)
For other kinship terms similar to 형, see http://hanguladay.wordpress.com/kinship-terms/
Many of these kinship terms (especially and particularly those for “older sister”, “older brother”, “uncle”, “auntie”, “grandmother” and “grandfather”) can be used for people who aren’t related in place of the word “you” (which Koreans tend to avoid), and also in order to refer to someone, like a name. And, there you go. ^_^ 형님 (hyung-nim) is an honorific Korean term of address for a male’s older brother. I hope that helps!