de- +‎ factor, modelled on earlier refactor.

defactor (third-person singular simple present defactors, present participle defactoring, simple past and past participle defactored)

1. (programming, rare) To modify source code to remove design patterns and structure, for example to make it harder to reverse-engineer.
   • 2012, Godfrey Nolan, Decompiling Android (page 137)

     One of my favorite transformations is to use threads to confuse a hacker who is trying to steal code. […] Many of the transformations I've discussed go against the programmer's natural sense of what's good and right […] You also don't have to defactor (see the section "Removing Programming Idioms") if you don't want to; you can refactor too. Refactor two similar classes into a parent class, but leave behind a buggy version of one or more of the refactored classes.