Is it possible to successfully adjust predictive text for offensive words?
It seems that you can dis-associate the word from the phrase by deleting it as a suggestion. As per Get word suggestions &amp; fix mistakes:

Get word suggestions &amp; fix mistakes

On your Android phone or tablet, install Gboard.
Open any app that you can type with, like Gmail or Keep.
Tap where you can enter text.
Type a word. At the top of the keyboard, you’ll see suggestions:

If you see the word you want, tap it.
If you don’t like a suggested word, touch and hold it, and then drag the word to Trash.




I tried it out and I don't get the test word I moved to trash as a suggestion for the one that I dis-associated it from, but I still get it as a suggestion after other words.