One who believes his existence is unique for it is defined in "you are your life and nothing more." Someone who sees life in his own light and allows no one to impose on one's view of life. To question one's existance and how valid one's experiences in life are. One who takes life experience by experience, good or bad, and builds upon one's existance and reality. One give meaning to many and all.
I am an existentialist, I am just one who is because he is.