바람 wind, 만 a postposition to mean "only". 바람만 바람만 is an adverb to mean you're following something or someone from a distance although you're supposed/hoping to be walking right by them. Imagine you're following someone(that you used to walk with before) like that at night, you would learn to recognize the wind between you two. When other people see you, you look like following the wind. they would Actually it's said by some old people these days. In the song, a boy loves a girl that loves someone else. He can't stop his mind loving her and doesn't want to interrupt her love. In the end, the boy feels pleased with a little bit of sadness mixed in as he can see his love at least. This is how the song goes.

It is an old korean vocabulary.. so we rarely use it maybe don't.. that means, shape of a person who is following someone with a far away distance. like watching someone but the someone don't know who's watching me.. It can be one-side love or can't forget his/her lover.... but It's different meaning between a stalker and 바람만.