Does saying "gg" mean you agree to give up?

When a player says "gg" when it looks like they will ultimately lose, is that a formal concession and an agreement with your opponent that you will "give up"?
Another way to ask this, would you pass up an opportunity to Win a game solely b/c you said "gg" believing that you had no chance?
Another way to ask this, would you pass up an opportunity to Win a game solely b/c you said "gg" believing that you had no chance?