when someone makes something more douche-like than it was before

A term used to describe someone who disregards other people in pursuit of their own self-interest. Usually includes the acts or act of lying, spreading mis-information, covering one's own ass at the expense of others, or employing other forms of bullshitting.

To make illegitimate or to severely degrade the quality of

One born without married parents.

Besides all the usual meanings, it has a meaning in engineering as well. A bastard is a type of coarse-toothed file.

Extremely distorted. No longer resembling the idea presented by the original.

Those responsible for the death of Kenny on South Park.