I did some research into this before developing my game and the conclusion I reached was that it totally depends on what you are trying to do. Since a company cannot own a Trademark to a generic word, as I believe Jeopardy is, you should in theory be ok. True that it really comes down to how sensitive the Company you are copying actually is in terms of issuing a Cease & Desist, but still Apple has proven very sensitive to outside requests for take downs. So like the case in Tris, it wasn't that Tetris had a case at all but still Apple threatened to remove the app.
Bottom line, if you think there is going to be a problem change the name - don't risk your work for trouble down the line. I know it can be hard to disengage from a name you like but it is worth it down the line. For legal lessons I learned during the process check out my
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