If you dont want to see news or spoilers about TV shows you like in your newsfeed, one way is to of course unlike the Page of that TV show, or else you could just "unfollow" that Page.
However that will not stop your Facebook friends from writing about the TV show or posting spoilers that will show up in your newsfeed, and facebook does not have a native method for hiding such posts.
One way you can hide such posts is to use a browser add-on such as FB Purity, that lets you filter out newsfeed posts by keyword or phrase. Once you have installed it, just put the names of the TV shows you don't wish to see spoilers or news about into the Text Filter box, which is located on the FB Purity options screen, which you can access by clicking the "FBP" link in the top nav bar at the top of any Facebook page.
You can get FB Purity free here: http://www.fbpurity.com