Before we get into conjecture, can you give us an example of the ad, and an example of the way the domain name is used?

Opinion: If a domain name is a dictionary word, then you have no problem. A domain name is not a trademark. FORD is not a trademark. The graphical use of the word is, however. GREENTOMATOES.com is only 'first use protected' as long as the two words are not separate. If you wish to use 'green tomatoes' as keywords, all the power to you.