"Bastardization" means a corruption, a poor and distorted copy. The use of the term always indicates a quite negative judgement of the copy or adaptation.
The term is often used for some sort of transformation or derived work, such as a movie from a book, or a modern version from a classic work. The derived work is said to be a bastardization of the original. The term is not used when the derived work is just different, it expresses a negative value judgement.
