Liberalism

Liberalism is a political philosophy based on individual rights and social equality. It's one of the most prevalent ideologies in democratic capitalist society, despite being for complacent suckers. Liberals come in many different varieties, and are broadly represented in all major American political parties. Yes, conservatives are a kind of liberal, at least the ones who aren't outright fascist.

According to its adherents, Liberalism is the most rational philosophy of government and has existed forever. However to the best of our understanding, it really took off with a guy named John Locke who wrote about a kind of sandbox game called the 'state of nature'. He argued that people fucking around in the wilderness would eventually need some kind of state to protect their loot from griefers, and that this state derives its legitimacy from popular consent. He can be contrasted with Hobbes, who was based and put forth a concept of sovereignty in which participation in a given society entails an implicit social contract. Since the 17th century the theories of liberalism have evolved to encompass modern democratic governments. You still have some 'classical liberals' and 'anarcho-capitalists' who believe in a kind of propertarian minarchy, and these people can be called anarcho-liberals. There are also explicitly anti-democratic Republicans who support a constitutional administrative state.

Radlibs

Liberals who are infected with collectivism are called 'radlibs' due to their self-described radicalism. Despite their usage of leftist aesthetics, their views are really closer to social-fascism. You can identify a radlib by their use of tired slogans about the "one percent" or calls to "eat the rich". Most self-described anarchists also fall into this category.