liberalism vs ideology

liberalism and ideology both are nouns.

Word	Noun	Adjective	Verb	Adverb
liberalism	Yes	No	No	No
ideology	Yes	No	No	No

As nouns, ideology is a hypernym of liberalism; that is, ideology is a word with a broader meaning than liberalism:

liberalism: a political orientation that favors social progress by reform and by changing laws rather than by revolution
ideology: an orientation that characterizes the thinking of a group or nation

Other hypernyms of liberalism include political orientation, political theory.

liberalism (noun)	ideology (noun)
a political orientation that favors social progress by reform and by changing laws rather than by revolution	an orientation that characterizes the thinking of a group or nation
an economic theory advocating free competition and a self-regulating market	imaginary or visionary theorization