Think it was a series, trilogy maybe , about a boy who's name is a magic word. He only says the short version of his name because the long version of his name was the actual magic word. If you share the magic word it becomes less powerful and when you learn more words you become more powerful. At learning 5 words he and his girlfriend combine to become a God. Believe I read this in the early 80's, and not sure how old it was then. Thought it was Piers Anthony but did not see the book/series I was thinking of yet. Any and all help will be immensely appreciated.