"Left" and "right" are common parlance throughout the world. Where, roughly, "left" favours collectivism and social responsibility, and "right" favours individualism and liberalism (classical sense, not American sense).
Those are horoscopes. They may be commonly understood, (although you're wrong about how people use left and right as well) but if you want to call yourself left, you can match those statements to your opinions, and likewise if you call yourself right. So it is still the case that no one knows what you're talking about.
Liberty is a function of an extraordinarily strong social contract. If you don't have strong enforcement of rights, you don't have rights.
Moderate: between Republican and Democrat.
Progressive: left of Democrat