Bastardize

[Jason Yan]

To make or prove to be a bastard; to stigmatize as a
bastard; to declare or decide legally to be illegitimate.

[Julian]

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

[Dorothey Allen]

bas-tard-ize (Verb)

1. To [diminish] the quality or character of;

2. To [declare] or name someone a bastard; illegitimize

3. To fuck something up; completely [ruin] it.

[Zipporah Schumaker]

To make [illegitimate] or to severely [degrade] the [quality] of

[Hina Muqadas]

to change something in a way that makes it fail to represent the values and qualities that it is intended to represent