The word is 그대. The romanization is 'Keu-Dae' or 'Geu-Dae'. (I think the latter is better to pronounce it) It means 'You' There are some words mean 'you' as follow You can use each terms for each different situation. (1) 너(Neoh or Neo), It sounds like 'nu' of 'null'in English. 1.When you address your friend or sibling 2.When you address someone younger than you 3.When you address someone whom you are arguing with. fighting as well. 그대(Geu Dae or Keu Dau) - 그 sounds like 'g' or 'ground' in English. 대 sounds like 'da' or 'damn' in English. 1.When you (literarily) address someone you respect or love 당신(Dang Sin or Dang Shin) 1.When you address someone not really friendly with you. It may sound you do not respect him (in modern Korean) 2.When you humbly talk about a person to others, The person is elder and you talk about how the person is or what the person think Hope this helped and other italki members' going to correct something wrong or add what I didn't explain.

It's very polite word for call "you" Used to call for Lover.

he says "Geu dae" "그대" which means "you" but in the song its "your"