Tankie is a general term for someone who thinks there is a clear justification to use force or the threat of force to impose a socialist system on a state. The term originates with people who supported the USSR “Sending in the tanks” to annex other countries and crush dissent from people in their sphere. They are what people mean when they “If you go far enough left, you get your guns back.” These days they tend to be a tiny minority within the rather small minority of actual leftists. They do exist, and some of them are pretty out there, but not the way the .ml crowd tends to characterize them. They’re terrified of them, because in their heads the most terrifying thing in the world is a leftist that is willing to fight back, and they don’t recognize anything that doesn’t kill someone as “fighting.”