When a conservative says liberal, it just means Democrat.

When someone with a vague clue says it?

Liberalism is a political ideology that holds that the primary role of government is to protect the rights of its citizens.

What those rights are, and who the liberals consider to be worthy of protection vary but as a general rule the right to private property, some form of democratic representation, due process with at least a gesture to equality before the law, freedom of religion and expression tend to be core rights.

Historically liberalism is deeply invested in capitalist and humanist thought. You could probably argue that liberalism isn’t strictly required to be capitalist but quite frankly it’s unlikely that will change before humanity is at the point of free energy and absolute post scarcity productivity.

The founding nations of liberalism are, roughly, America, France, and the UK and it’s Commonwealth. If you want a intuitive understanding of what liberalism is in practice and reality, just think of their history in the past two centuries or so and the struggles of governance they have undergone.

Those aren’t the only form of liberalism however. Social Democracy (the so called Scandinavian model) is a form of liberalism, neoconservatism (GW Bush, Romney) is liberalism (in theory), etc. Even “right wing” libertarianism is ultimately a form of liberalism, no matter how much that upsets the ones that don’t know what words mean.

Anyways, political parties that officially call themselves Liberal tend to be fairly conservative by modern standards. It is a uniquely American degeneracy sponsored by Reagan that sought to call progressives liberals.

One might note that you can broadly characterize the defining ideologies of the past century into three broad categories.

Liberalism, Socialism, Fascism.

When a supposed ideological liberal like Reagan and his successors, modern conservatives say no, actually, I hate liberals and I REALLY hate socialists you should believe what they tell you, and consider what that makes them.

I would counter relative to the other answer you got that liberalism is based on a leveling of the political rights of citizens while resisting a leveling of economic rights (despite some calls for it even at the time). Feudal governments absolutely were also based on the defense of the rights of their citizens and indeed even some classical slave societies, but the difference is that those societies had [more pronounced and varied] castes which each had different political rights.

Liberalism was a revolution led by merchants and other propertied people against the aristocracy, i.e. people with the greatest economic rights opposing those with the greatest political rights, leaving the former completely unchecked except sometimes by popular power.

Incidentally, and this explains some of the bickering in this thread, communists of all stripes are people who advocate that both political and economic rights are leveled, which manifests as the economy being controlled by popular mandate rather than private ownership.

Anyway, I’m mainly commenting to say if you have other political questions, you can usually get very thorough answers from c/askchapo

Draw an equal triangle. One line is ‘public policy’, another ‘private interest’, and the last ‘state authority’. You can label the two endpoints of ‘state authority’ as ‘left’ and ‘right’. The third point is ‘liberal’ which lies in opposition to the political spectrum of state authority. Liberals tend to fixate on authoritarianism over whether it serves the public or private interest.

People rarely fall on the points or lines as all concepts are in perfect tension.