bastardise

To make a bastard doesn't necessarily have to refer to people. Giving a legitimate word a new meaning could be bastardising the word. Basically, it's butchering the English language. See orphaned. If you have an idea, and someone takes the idea, changes it around and gives it new meaning, that's bastardising. If you design a newsletter, for instance, and someone else takes over and keeps part of your design but applies elements that don't match up with yours, that's bastardising. You get the drift.