From bastard + -ize.

• (America) IPA: /ˈbæstɚdaɪz/

bastardize (bastardizes, present participle bastardizing; simple past and past participle bastardized)

1. To claim or demonstrate that someone is a bastard, or illegitimate.
   • 1765–1769, William Blackstone, Commentaries on the Laws of England, (please specify |book=I to IV), Oxford, Oxfordshire: […] Clarendon Press, →OCLC ↗:

     Our law is so indulgent as not to bastardize the child, if it be born, though not begotten, in lawful wedlock.

2. To reduce from a higher to a lower state, such as by removing refined elements or introducing debased elements; to debase.

   The simplified word processor is a less-functional, bastardized version of the full program.

   • 2017, Douglas Charles Kane, Beren and Lúthien (2017) by J.R.R. Tolkien, edited by Christopher Tolkien, in Journal of Tolkien Research, Volume 4, Issue 2, [https://scholar.valpo.edu/cgi/viewcontent.cgi?referer=https://www.google.com.au/&httpsredir=1&article=1077&context=journaloftolkienresearch Article 5],

     The third potential audience is the general public at large, who either never has read any of Tolkien’s books or perhaps read The Lord of the Rings and/or The Hobbit long ago, but whose knowledge about Tolkien’s created secondary universe comes, if at all, mostly from seeing Peter Jackson’s bastardized adaptations of The Lord of the Rings and/or The Hobbit.

3. To beget out of wedlock.

• (introduce debased elements into, to degrade) mongrelize, butcher, debase