Too many if's that are relevant to your question.
For example, AppleComputers.com
Basically two generic words combined, but right away the domain can be perceived as a property from Apple the world famous brand in connection with "Computers".
I wouldn't use or register this domain, and a lot of people that want to stay on the safe side wouldn't.
So if your situation resembles the above example, i would advise to pass up on it and look for an alternative domain.
ShellProducts.com - You could build a site offering products made of sea shells, but when you start to promote products similar to the products Shell the company brings on the market...you're shooting yourself in the foot.
So think carefully about the keywords you're going to use...and how you're going to use the site.
2 cents.