Liberalism is defined as "The quality of being liberal." and, in turn, a liberal is defined as "The adjective is from Old French liberal, from Latin līberālis ("befitting a freeman"), from līber ("free"); it is attested since the 14th century. The noun is first attested in the 1800s. and, in turn, a "freeman" is defined historically as a person that is not a serf or a slave (also, known as a city person, a burgher, hence the word "bourgeois", or, "people of the city").
The term seems to call back to the Magna Carta and the general idea that using various means, slaves and serfs managed to break off from the monarchy in order to become what is known as a "freeman", a person that is typically to be found living within a city that is also not a noble nor an outside trader. In principle, Freemasons are the very embodiment of "freemen", mainly because their attributions or roles within a "medieval city", map to the people within a city that would most closely match the definition of burgher; this includes mostly people of all trades, crafts and artisans that are not permanently commissioned by the Monarch nor are carrying out tributary work.
Due to catch-all politics (regardless whether that might be wrong or right, in ethical terms) but also due to freedom itself, the term "liberalism" remains both misunderstood and mostly used to label an arbitrary group of people by relation to its definition (ie: it would not be the factual case that the people "opposing" liberalism would rather adopt a system where they would be slaves to their own determent, whether human or financially). Instead, "liberalism" as a term applied to politics consists in just a spectrum, from more liberal, to the least liberal but mostly in terms of governmental policies and not in terms of individual freedoms that is a guaranteed universal right (with very few outliners that are not signatories of human rights agreements).