I've never heard it before and I watch Rick and Morty.

This is the funniest comment I've ever seen on HN, I snorted

I debated deleting it as it's more of a reddit sort of comment, but I like adding a bit of lightness to HN here and there.

I appreciated the check on the unnecessary condescension

Just play Civ

Or better yet just play Suzerain.

Sue is a what?

It could also be more common for non-native English speakers, for example native speakers of Romance languages.

I'm reasonably sure we were taught about suzerainty ("suzeranitate" in Romanian) during high school history lessons.

It's definitely more a "college level" term in the US, but very much undergrad, if that makes sense. Good chance someone who even minored in certain social science fields will know it (decent odds they'll have employed it on a written exam a time or three), plus most people who just have a hobby-level but long-running interest in those kinds of things. A good high school course might expose students to the term, but I doubt it's common, at least outside elite prep schools.

I definitely only know this word from ancient Chinese history in undergrad. The lesser kindgoms were always having to send tribute to the Emperors.