Ask YC: Stealing domains from the big dogs

Some time ago, I acquired a foreign tld name with the intention of doing a memorable name/url branding for a site I'm building. After I became attached to the name, I realized that the bottom level part of the domain is the same as the one for a rather large american .com (think sun.de but not sun or de).

My question is this: could the big company litigate and/or take the domain away from me? The branding of my domain is quite different from theirs, and it's done in such a way that it would take some effort to notice that they're the same.