Shōbu, when written 勝負, is the ordinary Japanese word for competition. It means, literally, victory and defeat.
聖武合気 shōbu aiki, however, as written here by Saotome Sensei, has nothing to do with winning or losing. Rather, it signifies the martially pure and saintly (聖武 shōbu) application of aiki (合気) within the world of human affairs.
聖武 shōbu is the ideal of the martial arts, their highest expression of intentionality and valor. It is the selfless practice of the martial way that can only be brought forth when the heart is free of all desire to conquer. 聖武合気 shōbu aiki, then, is the pure and unaffected rendering of aiki in service of mankind.