I don't believe there is a way to do it from the interface, but you can type it in the search box. So if you wanted all your mail in your inbox that wasn't from
smithj@domain.com you can do "in:inbox not from:smithj@domain.com" and that will get you the results you are looking for.
To take that a step further, you could enable the "Preferences->Show advanced search language in search toolbar" setting, then build your query from the interface, and prefix what you want to exclude with "not".