Sorry, I need this conversation grounded.
You are saying you would like to search for:
msft -msft_user
This is technically possible in our current index, but would require a bunch of work to get it going. Especially since msft_user gets tokenized down to two tokens (msft / user) so we would need to use the is followed by syntax. I can see the merit of implementing a - operator but it is not a trivial change.