The name that we'd like to use for a new web application is a 2-word name (e.g. "Leaf Quick", with a space) that's already a registered trademark in the reverse (e.g. "QuickLeaf", no space).
Both our product and the other company's are hosted web apps, but one is a consumer-facing application for photos and the other (ours) is an accounting application for small businesses in a specific industry vertical.
BTW, the names above are not the real names but are similar in that both names are probably Arbitrary Marks, with both words being common English words that have no meaning in either the photo-editing or accounting business.
What's the chance that our desired name will be infringing? I will be consulting an attorney but don't want to waste time and money on a name that's very likely to infringe.