HOI4ian
An idea or statement revolving around worldbuilding, roleplay, alternate history, or other media that is so ridiculous or over-the-top that it would only work in Paradox's WW2 Grand Strategy Game "Hearts of Iron 4." Often used in the context of having a nation inexplicably win a war or become a dominant world power for the sake of aesthetics, political victory, or powergaming.
"Dude, Germany could have won WW2 if they just produced more Tigers!"
"Man, that's so HOI4ian."
"Man, that's so HOI4ian."