liberal is a multi faceted term.
the word is derived from the latin word freedom, libertas.
So you could say it is a synonym for freedom?
well, yes and no.
First, there are historical events the term liberal is explicitly used for.
for example laissez-faire in context with constitutional matters,
or neo liberalism regarding economic science.

It always implies less contraints in comparison to most other comparable "concepts".
the idea behind liberlism is more accessible to those with knowledge & education,
as they are aware of its conceptual relevance.
libaralism is more like a foundation for freedom.