Connor McGregor, the UFC fighter, says that when he is in the Octagon about to fight, he is "free". I love that word and I think I know that feeling.
Being free means being only in the moment. It means you let external events ebb and flow. You react according to those events - sometimes you are passive and let the action dictate movement. Sometimes you are aggressive and dictate the action. You don't think about the past and you don't think about the future. You are free of fear, anger, happiness, and any other emotion.
You are in the now; you are now, now is you.
It's important to get to this place in the critical points in life. Those moments will define how your life unfolds, and to be totally free in those moments largely dictates the trajectory in which you go.