Imagine Bethesda had made and trademarked a game called "Scrolls" and Mojang then later made a game called "Elder Scrolls". Do you think things would have went differently?
Reason why I'm asking is that I just found a good candidate for a name for my game, but unfortunately it contains a word that's also the name of a well known game. A game Bethesda also has some claim on - ok he word is "Heretic", and I will also be using it as an adjective and not as a noun if that matters at all.
I can see there are other games out there that contains the same word, like Heretic Kingdoms but I dunno...

Same problem, honestly. The issues are whether it's a) recognizable (will you pop up on the original IP owner's radar); and b) likely to cause consumer confusion (if you actually want to fight it when they send you the C&D). If it's highly recognizable you're more likely to get the threat of legal action. The more invisible your product, generally speaking (this is by no means absolute), the less likely you are to face legal action. The more successful your product, the higher the likelihood of legal action if any of your IP touches a big pocket's IP. 

Thanks, I'm thinking it might even be worse since Iwould be using the entire name as part of the name for my game- yeah I don't have the pockets to fight a lawsuit. They would have to throw some resources at it since I'm living in the EU though but they could just C&D Steam etc. who would probably fold immediately.

Too bad - Heretic Heritage sounded so nice - I better look for another name.