How to exlude someone from your will?
The simple answer is if you don't want to leave any of your estate to a particular person simply don't mention them in your Will.
if that person is legally entitled to part of your estate there is nothing you can put in your Will to stop it happening. There are no fancy legal words or phrases that will allow you to override the law.
What you can do ...
If your Will is challenged in a court - of course you won't be around to explain to the judge why you excluded particular people - so write down your reasons and keep them with your Will.