What is a classical liberal?
Well it isn't a 'liberal' in the modern sense, thus the word 'classical' attached to it.
Classical liberalism is the philosophy committed to the ideal of limited government, constitutionalism, rule of law, due process, and liberty of individuals including freedom of religion, speech, press, assembly, and free markets.
The founders were classical liberals. In opposition to the founders were the conservatives. The Tories,the British loyalists, were the conservatives. John Locke is the father of classical liberalism.
There was a revival of interest in classical liberalism in the 20th century led by Ludwig von Mises, Friedrich Hayek and Milton Friedman.