Its kind of both, isn't it? As is the case with a lot of terms.

There's a difference between being sad and being a sad person. Or being depressed and suffering from clinical depression. Being angry and being an angry person.

Being selfish doesn't necessary make you a narcissist. But, you can definitely be a narcissist (defined as having an obsessive interest or admiration of oneself) without having NPD.

I kind of think a lot of people getting blasted for using the term, or over using it are actually using it more or less correctly as they're not saying someone is a clinical narcissist. Just that their thinking on a particular issue is self involved.