“Tankie” was originally a British slang term from the 50s.

In 1956, when the Soviet Union invaded Hungary, the British Communist movement was split over whether this action was cool, or sucked.

The people who thought it sucked derided their opponents who thought its cool, as “Tankies”, because the images in the newspapers featured lots of photos of Soviet tanks rolling into Budapest.

After this, it stops being used for the most part, until it started being reclaimed by socialists online as a tongue-in-cheeck insult to throw at each other. Because, let’s be real, it’s a silly sounding word that’s fun to say, and silly words are among the UK’s biggest cultural exports.

Eventually though, Tankie breached containment and started to be used by people who had zero connection to any kind of socialist movement or history, and its meaning began to warp.

I’ve seen Marxists, even those think the Soviet invasion of Hungary was bad, called tankies. I’ve seen Anarchists called Tankies, I’ve seen right wing guys who love trad russian Orthodox Christianity called Tankies.

It’s a word that doesn’t mean much anymore. It’s like when your grandpa calls Joe Biden “Pinko Scum”