In the United States, you can’t use ‘Super Bowl’ without facing a lawsuit from the NFL. I’m in London now on vacation and I see several pubs with signs about watching big football matches in June. Obviously, they’re referring to the World Cup. Has FIFA gotten as protective over the use of the words, ‘World Cup?’
They would struggle to, because there are other sports with a “World Cup” - cricket and rugby spring to mind, and I’m sure there are more.
http://www.fifa.com/about-fifa/marketing/brand-protection/intellectual-property.html
FIFA has trademarks on a few of the World Cup phrases combined with “Russia” and the year, but none on “World Cup” alone. But since there are other World Cups in 2018 I’m a bit surprised they have the TM on “World Cup 2018”. However, they have more lawyers than I do, and they’ve been doing this for all previous WCs.