special interest

noun3

1. •
   A particular political issue that is the focus of political advocacy.
2. •
   A self-serving group with political power; especially, a shadowy one.

   • And they're going to get the news--the true news--quickly and simply and entertainingly. And no special interests will be allowed to interfere with the truth of that news. — 1941
3. •
   A particular highly focused interest of an autistic person.

   • I'm dating a boy called Nick whose special interest is video games; he won't stop talking about Pokémon.