liberal arts vs subject area

liberal arts and subject area both are nouns.

Word	Noun	Adjective	Verb	Adverb
liberal arts	Yes	No	No	No
subject area	Yes	No	No	No

As nouns, subject area is a hypernym of liberal arts; that is, subject area is a word with a broader meaning than liberal arts:

liberal arts: studies intended to provide general knowledge and intellectual skills (rather than occupational or professional skills)
subject area: a branch of knowledge

Other hypernyms of liberal arts include bailiwick, discipline, field, field of study, study, subject, subject field.

liberal arts (noun)	subject area (noun)
studies intended to provide general knowledge and intellectual skills (rather than occupational or professional skills)	a branch of knowledge