Tested several different combinations and any combo containing the string “UNIQUES” is flagged as bad word, not UNIQUE, specifically just “UNIQUES” is flagged during naming in character creation when in all caps.
Turns out its a lock of 6 characters in a row being uppercase. I can have the name be SIX_UNIQUE_ONLY or any combination of words entirely uppercased so long as its not 7 characters in a row without a lowercase or other character separator.