Webster's Revised Unabridged Dictionary · 1913

Bastardize

Bastardize ({not transcribed}) , transitive verb

1.
To make or prove to be a bastard; to stigmatize as a bastard; to declare or decide legally to be illegitimate.
The law is so indulgent as not to bastardize the child, if born, though not begotten, in lawful wedlock. — Blackstone
2.
To beget out of wedlock. [Rare] — Shakespeare
3.
to change something (for example, art forms) so that its value declines; to debase.