I suggest you find an attorney in your state who deals specifically with these matters, or just go up to your local city hall where you apply for your businesss license and ask.
My collective knowledge (could be wrong) tells me that if the business is incorporated (INC) or is a Limited Liability Corporation (LLC), it would be illegal to use the name. That’s at a minimum. Like Joanne said, if there is a registered trademark associated with the name, don’t even bother.
Remember, the government treats corporations like individuals. They have rights, and in theory, it would be almost like “identity theft” to use the name.
I know how difficult it can be to come up with business names, but the best name is going to be one that is original. With the wealth of buisnesses in this country, you’re bound to come up with something that someone has already thought of, but the extra effort will pay off.
Err on the side of caution and really think outside the box to get an original name, then INCORPORATE, then brand it if you can.
In North Carolina, businesses must have unique names when they incorporate and are actually checked against the state database to make sure there is no duplication.
Even if I could, I would try to find another name, though, particularly if it is in the same line of business. Think about the business as being ‘your good name’. In personal training, our reputation is our most valuable asset, and I would hate it if I would be confused with somebody else.