(of a version of something) lower in quality or value than the original form, typically as a result of the addition of new elements

by the 1760s, English cookery books were offering a bastardized version of French dishes

change (something) in such a way as to lower its quality or value, typically by adding new elements

our biggest fear was they were going to take our script and bastardize it

declare (someone) illegitimate

the Act of 1534 bastardized Princess Mary