Self-improvement means "made of himself, by self improvement". It means "improvement of your own person by yourself. The term, but totally legitimate, is influenced by the English word "selfgrowing", or "selfimprovement". That would mean, self-growth journey, or improve itself. In Spanish you would say "made itself". Although the literal, but incorrect, translation would be, that someone has been "Autoperfeccionado", or "Autohecho".
