The word is an acronym, not a club. It is used loosely to describe ANTI-FAscist organizations of all types. Still, if he can succeed in going after a straw man like this, what's to stop him from unleashing the security forces of the state on Occupy, Feminazis, Ecofascists Jihadists, fake news media, liberal elitists or any other group seen as a threat, even if there is no outfit that can be clearly identified as an organized cadre?

Trump is simply floating an idea to see how many squeals of outrage he can provoke. Its like flinging pasta at a wall to see if it sticks. If it is circulated by the press and no one complains too loudly, and if his knuckledraggers express enthusiasm, it will become a tool in his saddlebag that can be quickly dusted off in the future to give pseudo-legitimacy to some paramilitary or law-enforcement action against his opponents.

"ANTIFA" is a catch-all term that can be used against generic enemies, like "terrorist", or "Socialist". The Russians and Chinese have been playing this syntactic game for years, using words like "bourgeosie", or "imperialist".