How to know if the name is a trademark?

I see that for some kw-s, the GKP shows TM next to it and for some it does not. I want to buy an EMD for a game that would be:gamenameEXTRAWORD.com

That game does not have the TM next to it in GKP. I know that does not mean the name is not a TM but where can I see if I can make a site with the name or not. My site would be legit and would not break any copyright of the game.

it's very easy to check whether it has a trademark or not. just go to the USPTO site

uspto.gov/trademarks/