What is the polar opposite of the Libertarian ideology?

I’m exploring different ideologies, which I really have no handle on whatsoever, lol. (Goverment was not my favorite subject.)

From what I can tell, Populism would be the closest polar opposite to Libertarianism (or maybe Authoritarianism is, idk.) Just reading Wikipedia articles is not really helping me a great deal because I’m looking for polar opposites in political ideologies/philosophies, not forms of government, and I find the organization of these matters on their site a little disorienting.

Anyone who can shed some light on this for me would be greatly appreciated. : )