After fighting with this myself for years, I found out the answer.
From Word, press Alt-F11 to open the VB Editor.
Press Ctrl-G to open the Immediate Window.
Type this line and press Enter:
Application.CommandBars("Research").Enabled = False
Note that nothing will seem to happen, but you can go ahead and close the VB Editor and Word. The next time you open Outlook, the feature should be disabled.
