 The writer of the book, Anthony Burgess (qv), lived for a time in  Malaysia [where his wife was beaten by four American GIs, thus  giving inspiration to this story]. In Malay, the word "orang" means  man,[this is also part of the derivation of the word orangutan,  the other half being derived from "hutan" meaning jungle] therefore,  the title of the story is actually a pun on the British expression.  Rather than a clockwork fruit, it is a clockwork man, which is, of  course, exactly what Alex has become by the end of the film.