Date: 2021jun30 Application: Microsoft Office Q. Microsoft Word: Location of custom dictionary A. I searched for my last name in c:\users\USERNAME\AppData\Roaming\Microsoft And found it in

C:\Users\USERNAME\AppData\Roaming\Microsoft\Proof\CUSTOM.DIC

You can edit it with Notepad to remove words you don't use any more. Or delete the file entirely if you have too much junk in there.