FOX13 News, WHBQ FOX 13 An “USPER” is a U.S. person, that is, an American who is willing to carry out jihad attacks for the Islamic State — that is, in MyFox13’s parlance, “radicalized extremists.” Radicalized in what? Extreme in what? They don’t say, of course. Video from MyFoxMemphis (thanks to Robert).