Target Keyword Domain - Adding another word to the end, will it affect me?

So I've read that if you want to target a main keyword you should have an exact match domain. So eg. blackhat.com (Let's assume blackhat was my main keyword), what happens if I made it blackhatuniverse.com)

Because I added another word to my main keyword, will it affect me? I say this because I am only targeting the words "blackhat" since its a low competition and has a lot of traffic.

PS. This is just a made up example. I don't intend to use blackhat as my keyword as I am just trying to get an idea.

bump......

It does dilute the keyword density of your domain name. That being said, you still have a good chance of ranking, in my experience.

yes it's right way